I have a GTX 460 which I bought after my 8800 GT died (I resurrected it later in an oven). My processor is good, though (i7-2600k). I didn't buy a new GPU when I upgraded. The PC I have is not a gaming rig, it's a RENDERING rig. If I used it only for gaming I would've gotten something cheaper. I have good render times (managed to render a 1 minute video in a week), but my weak card has problems while I'm modelling. Oh, and my RAM is miniscule (8GB). Trying to render realistic fur or grass is a fool's errand.
P.S. Talking of realistic fur, the new Tomb Raider game has real-time realistic hair. I can play on high, but the game is unplayable with that option on, even if I lower all other settings by a lot! I don't know what beast of a card you need for maxing out that game with realistic hair enabled.