Best Video Game Franchise From These?

I definitely put more hours into Gears of War than any of the others, and thought the first three games were excellent. I've never been a consistent player of the others, although Call of Duty held my attention with the first Modern Warfare and World at War.

Gears definitely has the more likable and well-rounded characters, and probably tied with Doom in terms of lore with both just under Halo, imo.

Not sure which I'd pick in terms of actual gameplay though, they all offer something different.