I never bought MW2 but the first COD:MW was probably the best FPS modern shooter ever IMO. The stuff I read about MW2 prior to it's release for the PC kinda ticked me off so I boycotted it, but I'm in a wait & see mode on MW3 or BF3.
I did just grab the per-release/beta of Red Orchestra 2 to hold me over, because the original had the best tank action out of any other game I ever played. The FPS part wasn't great but seems they have improved it quite a bit with this new version.