For me it was a trial and error process of finding the right one. 3rd time was a charm, and it seems to me it has more with the compatibility between your system and the video card than it does "which is the best video card." While I'm no expert (by any means) re: video cards, I did learn quite a bit through the process of finding the one for me within my budget. At the end of the day I spent more than I wanted to, but hopefully it will keep me satisfied for some time to come.
My first upgrade was a ASUS 560 ti, worked but just not quite well enough.
Second was an XFX 7870, this card was great but I had artifacting issues and overclocking sent me to a blue screen/restart (BSODRS's,) not good.
Finally now I have a MSI 660ti and for the most part am pretty satisfied. I do still get some frdrops on some bases and some maps, but I've been able to furball with 50+ around and maintain frame rates.
I'm sure the experts will be along to help soon. I hope you are a patient person, this is may take some time.
Also, I had some trouble with Newegg and their restocking fees, the last card I purchased was from Frys.com, while they can be a little more expensive, they do not charge a restocking fee on vid cards.
If you scroll back a few pages you'll see my threads on this same issue and the progression...You can click on my name and view my threads too.
Finally, it seems to me that my system for playing AH works better with NVidia, may not be the case for you, but I was not alone with the AMD artifact issues.
GL
