Go for the 7950, and a custom-cooled one at that, like the Gigabyte Windforce 7950 I just bought last week new for $319. Flashed the card (it has a dual bios switch) using the Gigabyte Windforce 7970 bios and now it's running nice and cool at 1GHz core and 1375MHz memory (the default is 900MHz on the Windforce 7950 - 100MHz above the old reference 7950 speed). Yes the card can go over 1100MHz, but I wanted to just flash the bios and have all the fan speeds and cooler keep the card below 70 degrees, which it does.
Of course, I have 3 x 1680x1050 monitors, so I'm running at 5240x1050 resolution, so I really wanted to get the 3Gb video memory on this card. All in all, I'd say a custom cooled 7950 with a dual bios is your best option. If you really don't want to blow over ~$250, though, you'd be better off grabbing a Gigabyte 7870. In Canada, you can get one for $230 after $20 MIR.