I currently have a 9800GX2 and I am looking to upgrade my 2 year old machine. My main goal is to be able to run Starcraft 2 at 2560 x 1600 on Ultra settings. I have seen reviews saying a 460GTX is all that is needed, but is it going to be that much of an improvement over a 9800GX2. I could also pick up a second 9800GX2 on ebay, but it seems like a bad idea to buy more old tech and 750watts might be cutting it close. I know SC2 is CPU intensive, so that is another concern. My system specs are below.
EVGA 780i SLI board
Core 2 Duo E8400 OC to 3.5GHZ
OCZ Agility 2 SSD
OCZ 4GB DDR2-800 Cas 4
Thermaltake Tough Power 750W Power Supply
Blu-ray/HD DVD Combo Drive
Windows 7 Professional 64-bit
Do it now and grab a decent price on the card..the longer you wait the less you will get in proportion of what the card will actually cost..the card price won't come down as much, but the GX2 will keep dropping. later add another another 460 for sli that will destroy a single 480...as well the 460 will run cooler in your system and consume less power..and DX11
good luck on whatever you decide to do..