thats a toughy... for the motherboards go for one with DDR2 RAM and either an AMD dual core or an Intel dual core. for the graphics card go for at least a 256mb one PCI-Express.
If you're getting an 8800 gt*S* then make sure it's SLI-ready (it *should* say somewhere in the description, if you're not sure just email the site you're buying it from). That way you'll be able to upgrade with a second one later for less than the price of a whole new card. Because by that time it'll be fairly old. What I'm saying is this:
If you get a GTS now that *isn't* SLI, in 2 years time when you come to upgrade, you'll have to buy a model *at least* newer than that to get any upgrade.
If you get a GTS now that *is* SLI, in 2 years time when you come to upgrade, you'll be able to buy one the same. It'll be cheaper than the other option, and chances are good that 2 8800 GTS's will outstrip any other single card you could have bought for the same price.
i would say slightly higher actually...i mean you dont want to take the risk of it blowing out again but you dont need much more, just enough to compensate
I had a 450w with my 6600 and it kept having problems... I've got a 500W now, that runs fine. But I'd recomend at least 600W - 800W would be a better bet to be honest. That way if and when you upgrade with a second card, you're not gonna have any problems. I shouldn't have thought that a 600 will reliably run an 8800 (even gts) if your other hardware's high end as well...
700's a nice compromise I 'spose, but I'd go for the slightly more power as a future-proof against SLI and other upgrades... Can't hurt (much... Your parents won't thank you for the power bill mind...)