I haven\'t checked out what the best perfomer of the GF.3\'s is, so just check the reviews, and if you get a good deal go for it.
And if your worried about the temps it would be covered by the warrinty, the only thing of concern is that the card will help to heat the system, and if you have a proc that generates alot of hear like an Athlon it can help to increase the heat since the AGP slot is right next to it.But I doupt that it is anything that you should worry about.
But the Radeon8500 is supposed to be out sometime next month, then nVidia will proply release a GF.3 Ultra and lower the price of the basic GF.3.