The only issue with going with the professional cards, either Nvidia or ATI, if you intend to do any gaming or run any apps that are based on gaming engines your performance will be pretty bad.
I had a Quadro FX 1000 some time ago and ran the one of the graphics somethingMark benchmarks and the performance was just horrible. I tried to play Wow and I thought my system was having an epileptic fit (lol).
I'm not sure if this is true any more, as the new Quadro's have CUDA cores in them. Even the Quadro 600 has them, as well as support for DX 11.
Imagination is more important than knowledge.