From the Warhammer Online Dev Chat last night...
"Question: What game would your recommend playing untill Warhammer Online is released?
Josh Drescher: Hellgate. OH WAIT, you probably can't yet. Hellgate is so very good. Also, hungry Hungry Hippos.
Adam Gershowitz: shhh Josh NDA
Josh Drescher: I mean...uh..."
And so do I. Go pre-order, now. Every other MMO and its brother is getting delayed, Tabula Rasa is good but not worth your hard-earned cash... but Hellgate is bliss. It's not Diablo 3... it's Hellgate 1. And you need to play it. :)