Single player in MW2 is crap and short. The makers have dedicated almost all the resources to the multiplayer campaign and it rocks. Its amazing and addictive as hell ive just reached half the ranking cant wait to unlock the ak47 at the higher ranks.
Long story short if your not playing multiplayer i advice you to sell your copy as you might still get a good price for it. I havent even started the single player campaign and i dont think i ever willhyeah: .
Have you tried the multiplayer of Modern warfare? I am still playing the Battlefield 1943 its still a lot of fun even after reaching the highest rank. The innovation people bring is just amazing. In 1943 there are couple of guys who act as suicide bombers they are really difiicult to deal with.