I post to Mibba (of course), sometimes post something to FicWad (not often), and I was once very much a fan of FanFiction.net, though I don't even log on to my account there anymore despite the 80+ stories I have hosted over there.
A friend and I co-mod and maintain a fanfiction and fanart community over on LiveJournal, known as
MCR_Creations, but it's rather slow-running due to there only being ninety-some members. But hey, if you want to join and start posting, neither of us would mind. ;)
FicWad was once a great place to post, before they began having server errors. Now you'll be lucky if you can get any of the pages to load the first time around, and I don't think they've fixed the problem with the proper review counts not showing up. *sigh*