The funny part is that this is the only machine in the house with a PCI-Express vidcard slot, everything else is AGP (yup, oooooold) or laptops. If there was a discarded PCI-Express card-carrying PC in the house, I probably wouldn't have bothered thinking about buying a replacement and just cannibalized the other machine.
Considering so far I've had no big problems with the generic 8500 GT (which allegedly only draws a measly 45 Watts, with the pathetic fillrates of 3.6/3.6 Gpix/Gtex per second), and considering that the noticeably better 9500 GT (power draw 50 Watt, fillrates 4.4/8.8) only costs 60$, I think I'll go with the 9500 anyway, since I'll probably wait another couple of months before I get the new machine. Plus, it never hurts to have a decent backup in relative proximity (if god forbid the new machine croaks) in the form of this computer given to somebody else in the household.
I've had recommendations for the 5850 HD (peak power usage of 150 Watts, fillrate 23.2/52.2), but the cheapest one I can find costs around 370 USD, so my two main "contenders" for the time being as my personal favorites (for the new computer) are:
* cheapest generic (at around 175 USD) 5770 HD, which allegedly draws only 108 Watts, but has also the not-so-impressive fillrates of 13.6/34
* the 700MHz core ASUS NVIDIA ENGTX460 DirectCU TOP/2DI/768MD5 (at around 275 USD), drawing around 165 Watt, fillrates 22.4 / 39.2
The 5770HD's draw is its cheapness, and it's already almost 4 times faster than what I'm already used to.
Plus, it drains very little power, so I don't have to get freaky as far as the PSU goes. Not sure the savings in the PSU alone would be worth it, but compared to the savings on the card, it adds up.
The GTX460 however has a pretty damn impressive performance for the price (compared to a 5850, slightly worse pixelfill, noticeably worse texturefill, and is also 100$ cheaper) - and it has (at least according to the manufacturer's site http://uk.asus.com/product.aspx?P_ID=kDBMQo8MICJfpxEF
) some decent cooling, so I wouldn't worry THAT much about it, especially since it only draws 15W more compared to the 5850 (and nowhere near what the other cards you mentioned consume), so I guess I would have used the same PSU for both, no extra savings there to be had.