Well, I suppose you don't want ff.net, though I'm still using it. No NC-17 allowed there anyway ...

http://www.nfiction.com/ This one appears to be a clone of an older version of ff.net. Comfortably easy to use. Or maybe that's just because I was already used to it from ff.net.

http://www.skyehawke.com/archive/ ... I think someone already mentioned this one.

http://www.transformersfanfic.com/ The only fandom specific site I post at. Transformers fandom, so I doubt you'll have much use for it.