Are you planning on dropping $250 or more on a graphics card any time soon? DON'T!
I'd advise anyone thinking of spending any kind of serious money on a serious high-end graphics card to put off that purchase for a few months and wait. Wait for what?
Well, first off, I'm seeing a diminishing return from high-end graphics cards. Seriously. Apart from Crysis, I've not come across a game that seriously taxes these high-end cards that ATI and NVIDIA have been putting out for some time now. I'm not sure what has happened to games, but they don't seem to be driving the hardware any more. maybe this is down to the fact that all the major games consoles are getting a bit long in the tooth from a hardware point of view, and since many games nowadays are a port of a console game (or will be ported to the consoles) hardware demands have to be kept in check. Or maybe it's that game makers have become wary of pushing high end hardware requirements onto gamers. Or maybe it's just that the success of games such as World of Warcraft have proved that the success of a game has little to do with high-quality graphics. Whatever it is, there are few games out there now that will be limited by the GPU as long as you have a middle-of-the-road GPU fitted.
Note: You might read what I've written above and think that I'm suggesting that multi-GPU technologies such as SLI and Crossfire are now irrelevant. You'd be right. Not only are the promised benefits of SLI and Crossfire a very hit-and-miss affair at times (with many games you actually initially see a drop in performance on multi-GPU systems, and by the time the drivers are optimized, you're multi-GPU setup is no longer cutting edge), but even when there are gains involved, these are small.
Tread carefully when wading out into multi-GPU waters - these technologies offer the chance to spend a LOT of hard earned cash for very little return.
Another gripe about graphics cards is how rapidly the become obsolete (or at least how rapidly a high-end card is superseded by a new high-end card). If you'd bought say an NVIDIA 8800GTX back in say early 2007, you'd have bought a card that even now is up there with the best and can still run modern games acceptably.
Another reason to put off that major GPU purchase is Windows 7. This new OS will bring with it DirectX11, and while this promises to be backward-compatible with DirectX10 hardware, I'm certain that there will be a performance overhead similar to that you see with DirectX10.1 running on DirectX10 hardware. Given this, that GeForce GTX 285/295 or Radeon HD 4870X2 that you invest in now will fade into obscurity rapidly once Windows 7 is out, replaced by dedicated DirectX11 hardware.
The sweet spot for GPUs at present is a HD 4870 with 512MB of memory(shop around and you should be able to pick up one of these for under $200) or a NVIDIA GeForce 9800 GTX+ with 512MB of memory (you should be able to get one of these for around $160). In both cases, if you shop around you should be able to pick up a free game with your purchase too, which helps sweeten the deal!