I just can't contain myself anymore. I bought a Visiontek 4850 card a couple of months ago. It was mostly an impulse buy and even though this is a ridiculously powerful card at an insanely low price I really broke my budget to get the $160 it set me back. I had to sneak it in the house because I couldn't justify spending that kind of money to replace a card that still worked just fine. Normally I am prone to buyers remorse, but this impulse buy has been WONDERFUL. If you want to update your system on a budget the 4850 is an amazing performer. I'm so in love with this card.
I can't think of a computer hardware purchase that has ever made me this happy. It bought my aging (socket 939) system a new lease on life. Really this card just puts a HUGE smile on my face. It runs Fallout 3 at 1600*1200 Ultra high settings and everything maxed. My system is basically 3 year old tech and I can still play new AAA titles at higher graphical settings (comparatively) than I ever have in my gaming career up to now.
I've always bought mid-range cards (ATI 9700, Nvidia 6600GT, ATI X1950Pro, ATI 4850). I usually buy a bargain mid-range card. I spent LESS on the 4850 than I have any other video card on a game machine and it blows everything else out of the water. I know the 8800GT (512) has a lot of fans for its price/performance niche, but I'm sure the 4850 sets the bar even higher.
Anyway, I just had to rhapsodize a bit. I spent $160 on a card for a 2.5 year old machine and suddenly I can play the latest AAA title at ultra settings. Woot!