All 8800gt's use the same graphics chip, so the only differences in performance will be down to the amount and speed of the memory, and the clock speed of the chip itself. After that you should be looking for a decent warranty, and a cooling solution that doesn't sound like a hoover.
I'd suggest you read some reviews of specific manufacturers' models.
I had 2 MSI cards before the one I have now and MSI graphics cards are excellent. And since its the retail pack it will probably some with loads of extra cables etc as mine both did and I assume MSI haven't changed that.
Anyone want to lend me £146? Well give me £146 to be honest as I'm broke?