I'm a huge fan of Killer7, but I heard from one of my good friends, who was also a huge fan of Killer7, that No More Heroes was an extreme letdown, so that's what held me back at first.
I have yet to play No More Hero's. I really want to pick up Mad World as well.
If you pick up Dragon Age: Origins right now, you'll get two DLC's for free. They're going to stop shipping them with the codes though soon. I don't know exactly when, but I think it's April. (Please don't quote me).
Have you checked out Dragon Age: Origins yet? I haven't gotten far in it at all, but it's a pretty awesome game. It's what I've been playing on and off lately, due to the fact that I got burnt out of MW2 after a prestige and a half...