to add, CoD isn't bad, but it's worst than Harmony of Despair when it comes to recycling.
my honest opinion, Get 1 Modern CoD and 1 Past setting CoD, Stick with em because all the others are pretty much the same.
This is what I did exactly. I got MW2 Hardened Ed. for $40 new, saw all the maps for World at War on sale for !2 bucks or so, then bought a mint World at War on eBay for $10. I skipped Black Ops, and will skip MW3. I bought Battlefield 3 instead and am enjoying it quite a bit. I will likely buy a Call of Duty game on the next generation of consoles however. I wouldn't mind seeing a WWII/Vietnam or a Modern type in some amazing new graphics. So maybe the 3rd Call of Duty game on the next gen systems ha. As is is I have quite enough multi player shooters to keep me good for a while on 360. I'm just sad two of my friends bought Battlefield 3, then bought MW3 as soon as it came out. They have not been on BF3 since, oh, if I'm lucky I can get them on Gears 3. I think Battlefield 3 was too much for them to handle personally... I however recently got into Conquest and am loving it as long as I'm not getting raped too badly.