The latest known good nVidia series is the 7x0. Although it seems that much of the early run of 9x0 was also safe, it's difficult for us to determine if a card will or won't be until we see it.
If I had to get another card today for my gaming PC, I'd probably get a GeForce 670SC from EVGA. It's still beefy as hell, has 4GB of video RAM, and I know its output is flawless. I might order one anyway while I still can, from eBay.