This is a rather complicated topic. Especially since we now live in a post-modern era without clear definitions or truthes (especially concerning personal beliefs and religious outlooks). Also, we like to use the same word to mean multiple things. In my opinion, that is why the word "love" is so messed up (how can you "love" pizza, "love" your family, "love" your friends, and "love" your spouse... there should be, at least 4 different words). But, that is getting into a very different topic.
For that reason, I believe that everyone will define "church" differently (to a greater or lesser degree). Before I go further, I want to make this clear: I don't want to get too theological, so please correct me if I cross the line between defining/spiritual/etc and theological. It is my goal to provide a possible viewpoint, but this comes from my own personal thoughts. I don't think that anyone should wholly adopt my viewpoint. Quite the opposite, I think that each person should define what "church" means for themselves. It is easier to relate to something that is personal, instead of defined by another. All this said, I hope that my ideas are not controversial. That being said, I've tried to bring this to a philosophical/psychological perspective (instead of biblical) to avoid theological arguments/debate/upsettingness.
I see three definitions of the word "church." Each has a more personal meaning to me.
1) Church as a describing noun - This could be simply defined as "a place for religious or anti-religious practice"
2) There is the traditional view of the proper noun, Church - This can be defined as the whole group of "believers" (whatever that looks like, I'm not certain)
3) The last one is my personal ideal for what a "church" should/can/might be. This is, of course, going to be shaded by my understanding of the world and what is missing in the world. I expect this to vary greatly between people.... even those who attend the same "church" services. So, here it goes: The church, to me, is a place where different people can come together in an environment which fosters community due to a single unifying reason: One common and absolute belief. This will look differently for each person, culture, and region. But the basics, I think, are as follows: True community, spiritual growth (and/or pursuing truth), mutual support, and a certain knowledge-based teaching.
I'll leave it at that. Although, Zeke, I am curious why you posted this question?