@Mendicate Bias
Ah, I quickly read through the list, didn't know it was revenue based. Diablo II more than WoW? Wow, that surprises me (though I love Diablo II, I can't count the number of hours I've sunk on that game).
Anyway, we'll agree to disagree on Halo, but I can agree with you that you are correct that it has shaped FPSs this decade. So, I guess I'll say this: Halo has been very good to the genre and helped break it into the "more" mainstream (I'll argue it was pretty mainstream before that just not console mainstream due to lack of dual analog sticks).
Kind of lame that the IGN list is just the GOTY for the different years, but I guess that depends on how the list was defined, I thought it was defined as "best games of the decade", how foolish of me.