I've been using my PC since the end of 2004, AMD3400+ 64 bit, gig of ram and a Geforce6800Ultra (AGP on an ASUS K8N-E AGP board). I keep it in tip-top shape and have seen it get an extraordinary excellent score in PC Performance tests.
I only play my games at 1024X768 because I have a small monitor, but I like playing with high detail. The last game I played was FEAR which ran perfectly with these settings.
I'm going to get Hitman 4, can I expect the game to run well?
Sigh...I remember when I got this PC it was the best available dealers were flabbergasted that I wanted a 6800Ultra.
(I generally don't upgrade, just splurge on a whole new rig every couple of years)