I actually agree with origin here, I think the 8800GTS 320MB is one of the best bangs for your buck you can get right now. If you can afford it I would advise you to seriously consider spending the extra cash. You can get one with the rebates and mail-in rebates for about $250 right now and it will serve you well for quite a bit longer than a card you will pay $150 for.
Obviously sometimes budgets are steadfast and if that is the case for you then I would say don't worry about it, but for anyone with the means, do yourself the favor.