Best graphic card setup for the XPS 730 H2C ?

I'm going to buy an XPS 730 H2C with a QX9770 and Vista Home Premium x32. I was wondering which GPU setup would offer the best performance at 1680x1050 resolution:

1- Two 9800gx2 cards in Quad-SLI (pro: great performance; con: overkill for stated resolution?, noisy cards)

2- One 9800gx2 card, wait for the GTX280 to get cheaper, and then get two GTX280 in SLI (pro: good performance in the meantime, less expensive; con: lesser performance, noisy card)

3- Two 8800GTX cards and place in SLI (pro: good enough performance for most games/applications, 768MB RAM x 2; con: older cards)

I'm just not sure if the 9800GX2 cards would offer a significant advantage at the specified resolution (22 inch widescreen). This PC would be used for high-demanding graphic programs and gaming. I have no interest in buying a larger screen.

Additionally, I have to take into account the fact that the GX2 cards are much more expensive and that they are also, from what I've read in reviews, much more noisy, hot and power-hungry than the 8800GTXs.

So which choice would you go for?