Well, I agree that an old PC can be made much faster by clearing out the cobwebs. But as you said, the idea that a new PC and a 3-5 year old pc will perform equally on games and media creation is false. The people who aren't gaming or doing media creation generally just want a web portal, in which case, yes, a 3 year old box will be just fine. Seems we agree on everything, but just had a miscommunication
Oh, and I, too, was not counting Vista because I'm assuming the PC in question is not owned by a masochist