Black Ops: M14/Grip or ballistic knives/tomahawks.
MW3: Never played. Know enough about it not to want to.
Black Ops 2: SMR or Assault shield/Ballistic Knives/Tomahawks. Considering it has the same issues MW3 had, I feel foolish for buying a poorly made product.
At the very least, I can still have fun with an assault shield to mitigate the lag compensation BS. It only really works against mediocre to poor players who gladly empty their clip in to my shield thus erasing their two second head start.
The next installment will be Redboxed before I purchase it..