I'd say Dead Space. Fable II looks awesome as well, mainly because the first was really fun and the second looks like it improved from Fable on almost every aspect.Dead space or Fable 2. i'm really excited for both and will get them both eventually but since i'll only have enough money to buy one when it first comes out , the question is which should i get first.
I said Dead Space 'cause from what I've read and seen this game sounds like it's going to be loads of fun, and it's really innovative too, so Fable II could wait IMO.