I've not played Fable 2, but Gears 2 is amazing, and only comes close to Bond as the most fun I've ever had playing a shooter.
I've heard Fable 2 has more "charm" than any other game this year; and its general story is likely better than Gears as well. In terms of pure fun and gameplay though (not to mention whats arguably the best graphics of the year), you can't go wrong with gears.







