I thought that one of the best selling points of G4WL was for designers to bring X-Play for PC and Console versions of games - I thought after Shadowrun and Lost Planet: Colonies Edition, we'd see more of that. It'd be great for Fable 3 to be on X-360 and PC - and have both be able to play together.
Though, I'd really still love to see Fable 2 come to the PC, as well. I'd buy it most definitely. I really enjoyed Fable: TLC PC - buying it the day it was released here - and would love to see more of Microsoft-published games on the PC.
While we're at it - Fable 2 and Gears 2 I would also welcome on the PC. I think Microsoft should look closely at Steam's business model, fix up G4WL, and follow suit. I think the Batman: AA PC sale from G4WL last week was great.