Don't know if this is finally a price drop or if it is currently on sale, but as of now, Gears of War 2 - GOTY edition is $19.99 at amazon.
http://www.amazon.com/Gears-War-2-Game-Xbox-360/dp/B002GN8HU4/ref=sr_1_1?ie=UTF8&s=videogames&qid=1291363928&sr=1-1