On individual platforms, Halo Reach will be the best selling, meaning it'll outsell COD Black Ops on X360 alone. PS3 and X360 Combined is another story but I still think Reach will sell more than both platforms.
Killzone 3 is definitely not 2010.
Not interested in Medal Of Honour
Crysis 2 will hopefully kick ass and deliver a very solid FPS Campaign and Multiplayer.
Review Wise for 2010, it'll go Halo Reach with 94, Crysis 2 with 92 and Medal of Honour with 88.