I've used a number of NVIDIA cards, all without any problems, especially since upgrading to Liquid 7.2.1 (a free upgrade), and have used the fx540, GTS 8600 and the GTX 260. You'll find that the GTX 260 is the newest of the cards which have been listed so far, and yes there are a multitude of manufacturers selling this board. You'll find that NVIDIA is actually the manufacturer of the IC (computer chip) and all of the 'other' manufacturers make the daughter boards (or whatever you'd like to name them) using the ICs.
If I was to purchase a new graphics card today, I'd purchase any of the GTX 2xx range, as they will help with GPU rendering speeds, etc.