The nVidia GeForce GTX 460 and 560 series are pretty good, at okay prices. You didn’t specify how much you’re looking to spend, or the details of your hardware, so I’m not sure what range of card you’re looking for. They have cards for almost any budget, but I probably wouldn’t go under the 460’s $150 price point.
I picked up a 460 for playing Diablo III in my living room, and have been very happy with it. That said, if you’re going to be using Reality with the GPU accelerated rendering, you’ll want to spend a good bit more, and will be looking at an entirely different range of cards.
Sounds like you should upgrade your PC, though, also…