I've always been against the idea of MMOs, just becasue I'm not really down for paying for an item after initial purchase.  Even for DLC.  I've bought my fair share of songs over the Rock Band store, and I purchased the CoD4 map pack, but thats pretty much it.  But this game might be the one that would put me over the top.  I have two brothers are a good deal older than me, and they were pretty into the table top game, so I've kinda grown up with the universe in the back of my head, art style and the sheer brutality of it all.  

I've never played the Dawn of War series myself, but considering how many big MMOs are overhyped to be the next WoW killer (Vanguard, Age of Conan, Aion and Warhammer Online for instance) and disappoint in dethroning the top MMO, I doubt it would be a definite WoW killer.
 
However, it does look very good at the moment, and I hope they pull this off correctly.

hope its better then the other warhammer 

Relic isn't making it, vigil is. 
I have a feeling it won't be at all like dawn of war, which is a bad thing

This or Old Republic would put me over the top to try an MMO for the first time.