I would say leadtek, Gainward, BFG, eVGA the rest . Gainward and BFG is nice because it´s factory overclocked but Leadteks overclocks better so I would choose that. That is with the 2.0 ns versions some may ship with 1.6 ns memory. And when Gainward gets their copper cooler out it would be nice to see how it performs compared to Leadteks copper cooler.
I had a HORRIBLE experience with EVGA. I bought a 5900 ultra last year, right when they came out. EVGA was the only brand out, so I bought it. It didn't like to run, and EVGA tech support had me try all the usuals, then even gave me another BIOS to try. Nothing worked, so I RMA'd the card. The card they sent had the same problems, and so did the next, and the next. Finally they sent me a working one. I sold it and bought a Radeon 9800 Pro. When I jump back into the NVidia GPU scene, I'm going BFG and/or Leadtek.