I just got Bioshock yesterday, and it is not running at an acceptable level of awesomeness.  Immediate remedy is required!
 
So:  I have squandered essentially my entire work day researching graphics cards in the quest to upgrade my Geforce 6800 GS.  I have it narrowed down to:
 
X1950 Pro 256MB (currently around $140 from Zipzoomfly)
X1950 Pro 512MB ($170 from New Egg with tax and shipping)
X1950 XT (around $185 from eaglebit, which I have no experience with.  Free shipping, albeit 7 day ground.  Did I mention I want to be playing as soon as possible?)
 
OR
 
I take the plunge and go with a eVGA 8800 GTS 320MB from zipzoomfly for $290/270 after rebate (the crowd goes wild).
 
After all, what, in the grand scheme of the cosmos, is another hundred dollars?  Consider:  I expect to have money left when I die.  This money would traditionally go to my heirs.  These heirs do not, at present, exist.  
 
Am I to be beholden to nonexistent loved ones?  Fictional family members?
 
I SAY THEE NAY!
 
Still, there's no need to go completely insane.  Here's the issue:  I'm only running a Athlon 64 3700+ processor (with 2GB of RAM, at least).  Do I cheap out now and possibly get yet another video card when I upgrade the processor/motherboard (hello PCI-Express 2)?  Or do I go hogwild knowing this will last me through the next major upgrade?
 
Then there is this "step-up" program from eVGA....what are the chances there is going to be something worth upgrading to in the next 90 days?
 
The other problem is I can't for the life of me remember what my PSU is.  I need to look when I get home.

The X1950 XT is the obvious best bang for the buck.  
 
But if you can afford the 8800, you won't be dissapointed, either.

XFX PVT80GGHF4 GeForce 8800GTS 320MB 320-bit GDDR3 PCI Express x16 HDCP Ready SLI Supported HDCP Video Card - Retail  Free Lost Planet DX10 game w/ purchase, ends 8/31
 
http://www.newegg.com/Product/Prod [...] 6814150171
 
$279.99 with $30 Rebate = $249.99
 
You get the great performance of the 8800GTS for $250 and a Lost Planet disc! And I simply love Lost Planet for PC

Yeah I agree with Cleeve and Emp.
 
Either the X1950Xt or the GF8800GTS on sale.

Oh what a surprise. GrapeApe suggests an ATI card even though its way slower than the nVidia. Apart from  performance, the X1950XT is only DX9. The 8800GTS is DX10. Bioshock is a DX10 game.  
Actual data? : http://www23.tomshardware.com/grap [...] &chart=318
 

Oh what a shock NIZ complains about someone recommending the best options from both companies instead of just his favourite.
 
And Bioshock is DX9 & DX10.
 
As for your data did you even read it? Look at the information in the link again;
http://www23.tomshardware.com/grap [...] &chart=318
 
Thanks in advance for providing evidence against your own choice.
 
According to your chosen data the GTS achieved an overall FPS of 1827.8 which divided by the cost of the GTS in EMP's link ($249.99) gives us 7.31 fp$ , now compared to the X1950XT with 1494.9 FPS divided by the OP's price of $185 that gives us 8.08 fp$; proving with the data you yourself provided that the X1950XT offers more Bang/Buck.    
 
Man, I bet you feel like a real nVidiot right about now dontcha?    
 
Ah no matter, I still think either one is a good choice regardless of NIZ proving that some GF8800 owners are idjits. Don't worry it's not the card's fault, he started out that way before he bought one.  

Oh snap.

Yea, find out your PSU dude

lol niz...why dig your own grave?
 
@OP: Someone on this forum has been running it on the x1950XT at max settings at a reasonable resolution without a problem, so that would be your best bang for the buck option.
 
However, if you can afford that 8800 then that would probably prove more usefull in the future.....who knows...
 
oh and as randomizer said....psu details please
 
we wouldnt want you buying a card just to find out you need to fork out another $100 on a psu now would we
 

AMDZone shows the game is barely playable @1600x1200 for a 7900GTX averaging 22 fps and the 7900GT was unplayable with 14 fps.

What about his CPU, would that need an upgrade too to keep up with the 8800 GTS?

 
 
8600Gt 962fps overall, $100 9.62fp$
 
I wouldn't suggest it for gaming though, just like I wouldn't suggest a 1950xt if you can afford a 8800gts
 
On a side note my 8600gts runs bioshock at 1600x1200 DX10 in vista 32 with 2x AA&AF over 40fps

Yeah, just like I wouldn't suggest the GTS-320 for a DX10 future if you can afford to get the GTS-640 or better.  
 
There's of course other considerations than just fp$ , but as NIZ's own 'data' it doesn't support his reco / criticisms which is what's just so laughable.

hmm, with the CPU, is it dual or single core? if it's a singe core I'd hold off on the graphics card until a complete system overhaul, if it's a dual core you should be OK.  I say this with respect to future games, like Crysis and apparently valve will start using multiple cores better in future.  As for current games that are build for dual cores, i say lies, Supreme Commander still has a 98:7 CPU usage for my dual core.
 
Otherwise if money is an issue the X1950XT, but if you have the cash why not the 8800GTS and get the eye candy of DX10?

"step-up" program from eVGA'  May be a good reason to get the 8800GTS right there. It dosnt sound like money is a big deal here get the better card. If the 9800 comes out in Dec, you at least have a choice of an upgrade. It may be the only time the step up program would make a good choice.
 
 
Cheers

If you're upgrading because of Bioshock then go with 8800's or 2900's because the 7900's and 1900's are like midrange now for this game.

I think all those choices would be good for Bioshock (and probably crysis too).  It probably wouldn't hurt spending 100-150$ on a new dual core CPU either.  Hell, from the sound of your post, you should do that and get a 8800GTS from evga (just in case nvidia comes out with a card that is GTX speeds at GTS price) if you're not really that concerned about money.

bill gates?

So a 8600 GT with x2 3800 AMD and 2 gigs of RAM would be okay for decent settings on Bioshock? I'm in the process of doing a small upgrade on my son's computer which is a p4 3.2ghz Prescott w/2gig ram and 9600xt 128mb video card. Don't want to spend more than $300 if possible. Looking to buy 939 x2 and re-use 2gig's of RAM and thus save $80 on memory. BTW I'm using a 450W PSU w/28A on 12V rail (says 336W combined on 2 rails).

My other option (Which might be better) is to do a AM2 upgrade, using 3600 AM2/mobo/2Gig DDR2 800/and video card, for about $325 and getting $45 back on MIR's. Which would put cost at about $278. That is using the $115 8600gt evga card in that budget. What do you think?

I hear the Geforce 9 series is coming out in November, its still a rumor, but if you can wait that long it'll at least lower the prices of everything else.
 
But if you need something now, an X1950 should be good.  If you spend less money now, you'll be able to get into a 9 Series card quicker when they do eventually come out.  (But if y