I'm still playing DaoC and will probably pick up the newest expansion for that when it's released. The biggest downside to WoW would be Blizzards fan base imo. Like Xdaishanx pointed out, most of them are teh uber 1337 Wc players whom never played an mmorpg before. Other then dealing with them in game, the pvp/rvr factor just isn't there imo.
Other then DaoC i may check out MEO (Middle Earth Online). Just hope they open up the orcs as a race and add large scale pvp into it