Yeah, I agree with some who believe it is not important, just so long as it is biblical. However, atmosphere has a lot to do with the experiance of each individual. If you are into a megachurch scene you may be introverted and not want to be seen, you may like to be able to slip out of church wheneveryou want and not be confronted (in a good or bad way). This is also a negative with the mega church you are not able to hold everyone one accountable, you are not able to focus on everyones needs, some people get left out of the crowd. You may like mega churches because you are into more professional worship bands (which is not a bad thing, it adds to the experiance), you may like being part of a large group.
if you like small churches, you may be very extroverted and want to know the people you worship with, you may want to be involved in small groups and many of the ministries your church has to offer. you may not like the idea of being one in a million, but enjoy the idea of being one in a family. You most likeley are not introverted. ( I am an introvert and do not like my churches atmosphere, but it is the gody people and biblical teaching that keeps me there).
if you like house chuches your probably either or, you may be the type of person who likes your circle very small and you want to truely KNOW who your worshipping with. You may be fustrated with the amount of money being spent on paying for church mortgages and the pastors 4000 dollar a month pay while he has another good paying job. You may want to be in daily communion with your brethren and not once or twice a week. You may be extroverted though and like a BIG house church, if you are throwing it you may be very outgoing and hospitable, if your attencing you may like to meet new people who you are sure you have a connection with (due to the fact that you both know the owner of the home).
If you like other things like video, you may like being comfortable when you worship, you may have brothers and sisters who you are very close with who you like to worship with, but geographical issues don't permit you seeing face to face.
I'm not saying all is black or white, im just giving reasons why some people may choose or gravitiate towards some churches.
sorry for any typos, wrote this really quick.