Wright on 03 November 2015
This is a hard question for me. I definitively consider Gears of War > Halo, and I have some respect for Fable (even with all the problems that franchise has, and with Lionhead trying to destroy it with more unwanted spin-offs). Fable 2 was brilliant, and very unique. There's then Project Gotham Racing, which I consider gaming's best racing franchise - or at least the one I've had most fun with -.
I also checked and apparently they own The Movies (from Lionhead) as well, which is another brilliant game. And let's not forget Lost Odyssey.
All things considered, I'll guess Gears of War, followed very, very close by Fable.
