I've been using Obsidian Portal
to do a campaign wiki. The site is a dedicated site specifically for RPG campaigns, with some specialized resources. I would have suggested it to hrairoo for D'Andia, but he had already found one to use. I like this one, its fairly simple and the RPG specific setup makes it easy to use. Here's a link to the work-in-progress wiki for my tabletop - Fragments of the Far Realm
Rorschach's Journal [Oct. 7th] - 327 she calls. It is my number. I take my Whopper and leave. The streets are my table. The sins of man are my condiments. Criminals are my napkin. She forgot pickles. Justice is dead.