I generally come to Wikipedia looking for information on a specific topic, though I do always check the Main Page just as a way to learn something new. My occasional edits are usually in reaction to something I see (fixing grammer or bad links) or to something I don't see in regard to whatever it was I came to find in the first place.
I have no specific areas of interest on Wikipedia, and don't consider myself a maintainer of any specific topics or articles. In general I don't create articles because I don't have a lot of resources on tap to provide sourcing for information. I need to get in the habit of going to the library to write/edit an article or two, but usually I find myself just giving up on an edit for lack of time.