Gears of War: Ultimate Edition

Reaching level ten in online multiplayer requires 27125 EXP.
It is possible to jump from 0-10+ from a single game of Social KOTH, as you can get 20-30k EXP if you play well enough.

Also! The Gears team will sometimes do multipliers for EXP based on holidays or events which will make leveling much easier (I went from level 3 to 11 in a single game of Social KOTH on a multiplier for gearsmas).

Here is a great chart for displaying the level requirements!
http://www.gow3exp.com/gears-of-war/level/all
(Note this game uses nearly identical requirements for leveling from GOW3)