This was a question that was repeated many times throughout the Emergent conference in Albuquerque a few weekends ago. It was the central question of a talk given by Phyllis Tickle as she shared ideas from her book The Great Emergence. Her basic premise was that every 500 years or so, the church (universal) goes through a rummage sale of sorts because the institutions of Christianity become overly bogged down with themselves. Then "reformations" happen, when everything goes on the table, and the church must look again at where its authority comes from.
Everyone had thoughts on this throughout the weekend and it was interesting to hear the different perspectives. Most agreed that Luther's assertion of Sola Scriptura had the unintended consequence of forming a myriad of schisms... as different groups took away different priorities and interpretations from said scripture.
The central problem with schisms, according to Brian McLaren, were not the schisms themselves; but rather that each schism tried de-legitimatize every group above it (or below it).
The question of authority still remains, but here is my take on it. Any authority other than yourself is always going to be problematic. The minute you start relying on statements like "What my church teaches is...." then you have outsourced your discernment to someone else. You have removed yourself from accountability (or at least tried to). That is why, I believe, Peter set a standard of a priesthood of ALL believers. Hebrews concurs "in the past, God spoke to our forefathers through the prophets... but in these last days, He has spoken to us by his Son."
In the end, I will stand before God to give an account (Hebrews 4:13). I think the awareness of personal accountability is what is causing house churches and spiritual communities to catch on more. For many Christians, the days of being dependent on a Pastor are growing old. I think there will always be a need for an administrative authority in churches, but the assumption of spiritual authority has developed a generation who's discernment has atrophied. They didn't need it.... the pastor/bishop/priest told them what to think. That era, I believe, is coming to a close. I may harness my carriage to a teacher like McLaren or Claiborne at times, but I will always hold the reigns.
I think the upcoming generation will differ in that, rather than trying to de-legitimatize the paths of others, we will be looking to garner something from their view of life, scripture, and God. We will not feel the need to abandon the traditions we grew up in (though we will have the freedom to do so), rather we can view them as a sanctuary, but no longer the destination.