Have you played the game on a gaming PC to compare?
Obviously, Nvidia and ATI can't reinvent the wheel - their cards are just playing a ported game, so they will look very similar to their console cousins.
However, any decent gaming PC built in the last 2 years can whip the PS3 or 360 in terms of performance. Consoles only render MW2 at 600p and use upscaling hardware to fill up a 1080p TV. Meanwhile a PC renders it all, so everything will look much better. Throw in AA, AF, lighting, shadows and other fancyness and the PC version looks better.
However, this kind of game (console port) is not really the showcase of PC gaming power, though it does acquit itself rather well. If you want to see the true power, play something like Crysis and compare it to and pretty console game - its a different league.