I am currently in the process of updating my computer, and having a stable, graphics processor is one of the main aims, preferably one that can run 3D applications fast in Ubuntu, so I can fully migrate away from Windows. Rather than asking what card I should get, I think it would be more productive to ask (since so many companies now have Linux compatible cards), which cards don't really like Ubuntu that much, what cards should I avoid?

Anyway, your responses will be much appreciated as it will save me a lot of headache further down the line