BFG is a common favorite due to lifetime warranty and the best factory clockspeeds. I've seen few complaints about reliability, either.
Leadtek always gets extremely high marks around here for quality and reliability.
eVGA has the Step-Up program in case you think a 7800 Ultra might come out within 90 days at the same or similar price to what the GTX goes for now.
Bottom line, though, is every single one just has reference cards so there's little difference. And the chip hasn't been out long enough yet to give us any data on which brands' cards have better quality 2D.