I have been a fairly regular user on Wikipedia for a few months. I tend to read lots of articles I am interested in and make lots of fairly minor changes like disambiguation and categorization as I am reading and adding small tidbits of information. Sometimes I won't make edits for a couple days and then spend an hour or two on things like categories and adding info to infoboxes, (especially the Wikipedia:WikiProject Albums boxes).
I am generally interested in political and current affairs articles, articles relating to computer programming/computer science and computers, especially Macs. But I by no means stay within those bounds.
I also run User:BenjBot intermittently. So far it has only been used for disambiguation, but someday it may be used for more.