Well I run a Nvidia 280 GTX but only because I do high end graphic process's. How this how it comes when braking down between Nvidia and Radeon. If your looking to save money your going to want to go with Radeon. However, if your willing to shell out the cash you will and can see the performance increase switching to Nvidia. If you are new to Nvidia and you are looking for a good card for the right price I would pick up a 8800 GT for around $150 (but make sure you have a PCI-E slot on your current mobo). However if you really want to shell out some money you can pick up 9800 GTX (if your gona spend that much just go with the 8800 Ultra) which can compete head to head with Radeons current top of the line card (however does cost more but is worth it 2 GPU'S!!!). However if your really looking for something that just plane out will kill your bank go with the Nvidia 260 or 280. The retail for the 260 is around $360? I think not sure to lazy to look it up. The 280 starts at about $450 up to $700 something (would spent $450 because the main diff between prices is clock speeds which can be overclocked by yourself (if you know what your doing) and can save you a bit of money). Now why spend $450 on a new video card... Well there's a reason for which I refuse to type because my head hurts but take a look for yourself (
EVGA GeForce GTX 280 Video Card SSC Edition, 1GB GDDR3, PCI Express 2.0, FREE Special Edition EVGA Precision Overclocking Utility, SLI Ready, (Dual Link) Dual DVI, HDTV 01G-P3-1284-AR at CompUSA.com ). Now if you buy newer card I would also (if you have the money) pick up the new 790i mobo. New fast FSB and dimm slots support up to 2000 mhz (which means DDR3 Ram) and it supports the newer PIC-E 2.0 cards. Also a great manufacture for Nvidia based products would be EVGA. You can also go with BFG and PNY if you wish but the support and speed on most EVGA models win over BFG and PNY's. I am sorry if I left anything out are made grammar mistakes, my head hurts and it is late.