Warhammer 40k: Space Marine - 9/10
The only things I can really find to complain about with this game is the lack of dedicated servers, and the Ultramarines.
I would've given it an 8 for no dedicated servers, but the game is surprisingly smooth and stable online without them. Handles host changes quickly and seems solid. It needs a few more maps, but I'm sure we'll get those soon enough. I didn't really buy the game for the multiplayer, but I'm talking about it first because it's the last thing I was doing. Army Painter is great. I modified the default Salamander paint so it's a little more unique, but still staying true to my favorite chapter. My Chaos chapter however did not have its own default paint (Thousand Sons) and I had to paint it myself. Based on a class system and has a level up system (much like every other shooter lately), but it feels really well balanced and the action is quick and fun. I've had a little stutter here and there but that's due to my connection, not the game.
Now, on to the campaign. If you like 40k, you'll enjoy it. I was worried that they were only really showing off the Orks and it wouldn't have enough variety or would be too short. The campaign clocked in at about 8.5 hours for me and I found about half of the hidden items. Not bad for a modern shooter I'd say. Chaos makes and appearance, but no Eldar or Tyranids to be found. No Tao either (but did anyone really expect them to show up?). Anyway...I know some people have been complaining that it's very grey and brown...but that's how 40k is. The Grimdark has to be grim and dark. The final boss fight was fun, but I'm not sure how I feel about the ending. It felt a little like a cop out/cliffhanger, but it made sense I guess. Combat is very smooth from shooting to melee and never really got old for me. You're constantly switching weapons and once you get a hold of a Jump Pack (in a few missions) you get to have a blast.
Overall I think Relic really did a good job (and to think I was worried because they've only really done RTS game). I'd love to see a sequel that's Eldar/Tyranid focused. I'll be playing the multiplayer quite a bit in the weeks leading up to Battlefield 3 and I think I might play it after that every now and then as well.