My "centers" are three corners of my living room. Well, former living room, now preschool play room. One corner is a reading corner: books, chairs, pillows. One corner is dramatic play: toy kitchen, baby dolls, dress up stuff. One corner is blocks and puzzles.
All of my art and otherwise messy stuff is in another room because the living room has carpet. I wish it were all in one big room so that some kids could do art while others read or play with dolls. But as it is, I have to use one room at a time.
I don't know that centers are terribly important, but I think that others, like parents and consultants, think they are important. So I use it as an organization tool that gets me bonus points with parents.
