I'd recommend these two (they're browser based though, so be warned)

http://rpg-de.mo.ee/?ref=ohhpaigey (This one is coming out on Steam in 2 days, it has a pretty built up community, and it's doing quite well for itself)

http://www.valerpg.tk/?ref=1615 (This one isn't as active as RPG MO, but they're two different types of games)

I've been playing both this month since I canceled my WoW subscription lol.