well if you do want to stick with the gtx 260 i might be a little bias and say get an evga i personally have an evga gtx 275 ftw which has been an awesome card, and usually you'll get a free game from evga, i think right now it's cryostasis, and you get alot of awesome software, such as evga's precision which allows you to overclock your gpu by moving a slider, and that's it done, overclocked. but even with my love for evga, it's hard to recommend this gtx 260 because it costs almost as much as my 275 for the win which was pretty heavily overclocked at 738 core, 1651 shaders, and 2566 memory, So in all honesty you would be better off with ati 5770 or you could wait for the 5830, or the new fermi chips to come out
You DEFINITELY want to get the core 216. Follow up to from newegg to the manufacturers link if not sure. Mention to your DaD the pricing situation, and that right now the GTX275 can be had for a few bucks more. Heres a article where a lot of Nvidia and ATI cards from various vendors were tested against each other.
The GTX 260 holds it own very well. http://www.tomshardware.com/reviews/radeon-5770-overclo...
EVGA, XFX or BFG are awesome for sure, all with lifetime warranties. However, the GTX 260 Super Overclock from Gigabyte is kinda unique in that it delivers GTX 275 performance from a GTX 260. They also offer a 275 Super Overclock, which performs like a 285.
Make sure you get the 55nm, core 216 model. It runs cooler, and is more powerful than the older 65nm model.