I beat Fable for the first time this morning, and it hardly felt like 15 hours. I really hope Microsoft gets Lionhead instead of Activision, this series, if extended could very well be a true rival the Zelda series. As it is, Fable is one of my favorite Action-RPGs of all time. The time I put into this week felt like nothing, and I'd be glad to do it again. If anyone gets an Xbox, make this the one you pick up with it.
Also, if you're looking for good platformers coming out on Xbox, chell out Psychonauts. It looks exactally like Invader Zim meets Nightmare Before Christmas.