The earliest Christians may have worshipped in multiple settings, chiefly in people's homes, but perhaps also in buildings, "synagogues," outdoors, and of course at the Jerusalem temple. Over time, of course, Christianity became a legal religion (AD313) and then subsequently the official religion of the Roman Empire (AD380).  It is no surprise, then, that Christians began to build structures in which to meet.
Some strong voices today find this shift the bane of Christianity, a movement away from Spirit-led communal settings in the home to a more sterile, "institutionalized" setting where people participated less in worship and more watched it take place in front of them by a priestly class. Frank Viola, for example, says that the story of Constantine "fills a dark page in the history of Christianity. Church buildings began with him."  Clearly in his mind, the church went seriously off track when it started meeting in buildings.
We can understand this sentiment, and there is no doubt some truth to what they claimed happened back then accompanied by a move to worship in basilicas, the large church buildings of the day. But their analysis, particularly that of Viola, is not entirely accurate historically, nor does it relate directly to the question of buildings today. The "institutionalization" of Christianity had begun centuries before Constantine.  Indeed, it was already taking place in the later books of the New Testament, as we will see in later chapters. There are benefits and drawbacks to structure and organization. The key across the board would seem to be balance, not "rigid" spontaneity or rigid structure.
In the end, it seems quite wrongheaded to blame buildings for the demise of true spirituality in any time or place. It seems quite possible to be authentically Christian in any church, no matter what kind of building you primarily meet in. In this section we want to explore the main types of places where Christians meet today and try to look honestly at some of their strengths and weaknesses. The main options today would seem to be 1) large cathedral like buildings intended to accommodate thousands, 2) the average church building in the world, which accommodate hundreds at most, sometimes dozens, 3) the house church, which is best suited to numbers of fifty or less.
It is probably true that it takes greater intentionality on the part of church leaders for there to be significant spiritual growth on an individual level when the primary venue in which worship takes place is a large service that you mostly watch rather than participate in. This is particularly true of large, low church Protestant churches where the service mainly consists of listening to someone else preach. You might sing a couple hymns, but the special music is done by someone else on stage. Someone else gets up to give the main prayers. You do get to put money in the offering plate as it passes by the place where you sit.
We can understand the protests of the Frank Violas of the world against the backdrop of this dominant American form of worship. And most Americans who go to such churches only engage in what worship there is for about an hour a week. They are of course encouraged to pray and read their Bibles at home, but this is not corporate worship as a community of faith.
Interestingly, the participation element is at least potentially a little better in mainline Protestant churches, and especially in Catholic and Orthodox churches, where the congregation participates in most of the service. There are no special songs but all songs are sung by the entire congregation. The Apostle's or Nicene creeds are confessed by the entire church, as are confessions proper. The whole congregation says prayers together, including the Lord's Prayer, and they usually come together forward to take communion.
The usual low church Protestant claim that these prayers are "empty ritual" has of course often been the case in reality. But it is not necessarily the case at all, as we will argue in later chapters. It is more than possible to worship authentically and spiritually by way of set prayers and creeds, just as it is possible for a sermon to be inspired even if the pastor has prepared it ahead of time. A person can worship in a low church Baptist congregation where the people in front do everything for you and you observe. And a person can worship in a high church Roman Catholic mass where all the words are decided ahead of time.
A house church brings a number of potential strengths, not least of which is individual accountability to one another. In a large church setting, it is easy to hide without needing to submit to the broader body of Christ. While the kind of structure a person meets in seems relatively unimportant, meeting together per se seems an essential element of Christian faith. The New Testament does not specify where to meet. It does assume and urge that believers do meet together regularly with other believers (cf. Heb. 10:25).
Clearly the kind of give and take we hear Paul write about in 1 Corinthians 12-14 assumes a small group fellowship where the Holy Spirit is active. Men and women are prophesying, and anyone in the assembly presumably can. The early assemblies broke bread and worshipped together (Acts 2:46-47). The idea of a lone Christian whose life with God takes place on their own in the woods somewhere is foreign to the New Testament when there was the opportunity to meet with other believers.
So while nothing demands that Christians meet in homes, it does seem that a Christian life would ideally involve Christian fellowship in smaller groups than the typical congregation. Such meetings are not limited in any way to Sunday School classes or during the week meetings, cell groups or Bible studies. They could be going out to dinner with other believers or the many kinds of social interactions that take place between people on a more intimate level. The house church has no claim to be the only proper way for Christians to meet, but it has clearly captured an essential dynamic of Christian life sorely missing in many if not most churches.
The cathedral and mega-church building are offensive to many today, because of the immense expense they require to construct. In addition there is the objection of the house church movement that such large meetings do not allow for the spiritual spontaneity and accountability of a smaller group. At the same time, clearly they wouldn't draw such large numbers of people if they were not actually meeting someone's needs and desires.
The legalization of Christianity in the 300s resulted in many people coming into the Christian faith. Were they all true believers? Did this influx result in some syncretization of previous Roman religion and earlier Christianity? No doubt. Will there be more people in the kingdom than there would have been otherwise? Almost certainly. In the same way, it is hard to imagine that these large churches do not bring in more people to the kingdom and influence more people for good than some equivalent collection of house churches in the same area put together.
It is a serious question whether the expense of building such large buildings weighs against them. In the words of Judas in John, "Why wasn't this... money given to the poor?" (John 12:5). Indeed, when we think of the extravagance of some church buildings surely our consciences should be pricked.
And yet surely there is some room for meeting in the middle. Surely buildings should be built with a view toward true ministry, how to further the mission of God to bring good news to the world at a particular location in a particular facility. And of course at some point there is a place for using money to bring glory to God. Jesus himself allows the woman to spend her perfume on him. And there is something about the magnificence of the medieval cathedrals, built over the course of a hundred years by the very people of the community, stone by stone, that surely embodies the glory of God in a way no house church ever could.
The long and short of all this discussion is that we cannot say that any one meeting place today is the most Christian kind of place to meet. From cathedral to mega-church building to house church, each has its contribution to make. The cathedral points to the glory of God, just as God has adorned the creation in splendor. The mega-church complex can be structured as an instrument of the good news, with its basketball courts to engage the community, its Christian school to integrate faith with learning, and its sanctuary where thousands get a small foretaste of the ten thousands worshipping God in festal assembly (Heb. 12:22-23). The house church gets at the heart of the church, the body of Christ, which generally met in small groups of less than fifty. Here the kind of individual manifestation of the Spirit and mutual accountability can take place as God intends it to.
 There is a certain strangeness to the trend to see Constantine as the enemy of Christianity for "institutionalizing" it. For one thing, it was Theodosius I in AD380 that made Christianity the only official religion of the Roman Empire, not Constantine. Constantine merely legalized it, which in itself hardly seems something to protest.
And perhaps the most significant "institutionalization" move Constantine made was toward reaching some sort of agreement on the divinity of Jesus by convening the Council of Nicaea (AD325). In that process, Constantine was less concerned about what position they ended up taking as that the Christians become unified. It was then Theodosius I who made Nicene Christianity the official religion of the empire, as opposed to Arian Christianity that saw Jesus as the first of God's creations.
We wonder if those who cry foul to Constantine are happy to open the door to those who do not believe Jesus to be fully divine, a belief that at one point in the 300s was perhaps the dominant view. The legalization of Christianity also catalysed agreement on issues like which books should be considered the New Testament and which text of those books Christians would use in worship. As far as we know, the current list of books was not even suggested until AD367 and was not ratified by any council until a regional council in AD398. The all too common rumor that the Council of Nicaea settled the New Testament canon is clearly pop ignorance and about 100 years off the mark.
 Frank Viola and George Barna, Pagan Christianity: Exploring the Roots of Our Church Practices, rev. ed. (Carol Stream, IL: BarnaBooks, 2008), 18.
 Some would make a somewhat artificial distinction between "institutionalization" and "organization," where the former refers only to organization that is sterile and empty. Certainly if that is the way you are defining institutionalization, then of course it is always bad. :-)