a $3000 rig, would just laugh its ass off at an xbox 360, expecially in the loading times arena, its also more capable, can do what ever you want, better image etc.
But it also costs $2400 more.
Something I feel worth noting, my 14sih month old computer can run CoD 2, with texture quality high, 1024x768, 4xMSAA, everything else on high save for dynamic lights on normal, and no smoke smoothing.
Things different: lower frame rate, lower res (85% the amount of pixels the x360 uses), less dynamic lights (didn't notice any difference with this set to high, in IQ), and lack of smoke smoothing (again no noticable IQ difference, maybe I didnt look hard enough =P).
But then again my computer was built over a year ago, CoD2 cost $10 less, has the promise of mods, and I don't have to get up to check things on the internet.