ATI's new generation (DX11) video cards came out in the Fall....nVidia had a series of problems and theirs won't be out till March 26. Whether or not the 295 makes sense for you depends on whether you find DX11 necessary at this point in time. It's supposed to be the "next big thing" but then again so was DX10. Lotta peeps think DX10 failed cause Vista failed, and if they are right, DX11 should hold more interest to game developers. Only time will tell....and it should be summer 2011 before we can make a final judgment.
If you are looking for a GFX card to last you until then, then I see no real disadvantage in getting a DX10 card if it saves you money. If you want it to last well beyond that, then I'd say it's wise to make a choice on the best DX11 card you can afford. At the the GTS 250 / GD4850 level and below, DX10 cards have a place .... at price categories above that, I'd stick to DX11. The 4870 and GTX 260 remain fine cards but price bloat ($155 to over $200 in last 3 months) has pushed them out of the "reasonable buy" range.
Back in the fall, the 295 could be had for $450-$465. That's not a bad price for what THG had to say about it:
Despite ATI's new Radeon HD 5970 taking its place as the fastest graphics card on the planet, Nvidia's GeForce GTX 295 (with SLI-on-a-board) remains an extremely powerful graphics card. Essentially two conjoined GeForce GTX 275s, the GeForce GTX 295 offers very notable gains over a single Radeon HD 5870 in the great majority of game titles,
The 295 won the "Honorable Mention" moniker in the January's THG GFX card roundup...the same title that the 5870 got at $410 and the 5970 got at $625. Right now newegg's prices are:
5970 - $649 (1) $699 (2) and none of the 3 are in stock.
295 GTX - $509 (1) $519 (1) and $529 (1) and none of the three are in stock.
5870 - available at $399
In February, THG dropped the $500ish price category from the roundup and now only have a $400 (5870) category and a $680 (5970) category. That's unusual for THG to have a $280 spread and no category in between but the fact of the matter is the stock of 295's has all but completely dried up....and , while I can see the logic in getting a DX10 card at < $200 given the Dx11 performance of the 57xx series in DX11, I really can't see investing over $500 on a 295 when the next gen cards are just 31 days away.
So in answer to your question ....I'd wait till June when the cards have had a chance to compete for a while, both manufacturers get to mature their designs a bit more and competition starts to eat into both their price margins. With cards runnning as much as $100 over MSRP, I think it's time for us consumers to keep our money in our pockets until sales prices are < MSRP.