I'm getting Tekken 6 (360) + Smackdown 2010 (360) +

(either Ratchet or Forza 3; I'm leaning more towards Ratchet).
$30 Best Buy gift card too

As for Demon's Souls, it's not a grind fest at all. It's hard, and you're going to wind up replaying some levels over and over, but once you know what you're doing you'll never need to grind. It's very similar to an action game really; each stage is fairly linear from beginning to end (there are shortcuts), every enemy has attack patterns, bosses at the end of each stage, etc. Of course it's heavy on stats and crafting and everything else you come to expect from RPG's. DS is my GotY, and perhaps my favorite game of this generation. I'd go with that personally.
Oh, and if you DO feel the need to grind, there's a level that makes it a breeze. It's kinda broken tbh.