I have Pre-Ordered MW3 via Steam, it cost me just over $70 a couple months back which seems good to me and I got the original MW free (Already had a retail copy but who cares, free game right!).
I am a massive COD fan, not really for MP (Although it's pretty good) but for the Single Player Campaign, after playing through MW & MW2 I really want to see what they have come up with. Now on the subject of BF3, I've seen several flamewars about which is better, TBH I don't care, they trade blows & it really depends on what style of playing you prefer. After playing the Bf3 Beta for awhile I really don't want to get it for the MP, especially since it needs Origin, which is awful. Looking forward to hearing about the Single Player portion though :)