Computer will be used for both gaming and CAD. I have yet to buy a GPU as I'm not really sure what I need. I know the 2gb doesn't really help unless at x1200+ resolutions, but would it help for programs like 3d Max, Solidworks, Inventor, and Revit?
The speed of the memory (GDDR5 vs. DDR3 for example) may be more important than the amount of memory on the video card. You might find that these reviews provide some help decide what you need - it partly depends on whether or not your applications are designed for acceleration with nVidia's CUDA.
Which CAD and which OS are important. For AutoCAD and 32 bit Windows you can get by with almost anything that a monitor will plug into. For something like Revit you can benefit from a card that is certified by AutoDesk to work with it. (see the autodesk site).
For 64 bit Windows you might need a card that is certified to work with AutoCAD. We have run normal video cards with 32 bit Windows but that type of card would not work with 64 bit Windows because we could not get a 64 bit driver for it. (YMMV of course).
Typically it doesn't require much of a video card for most CAD apps. The reason is that you view a single image on your screen. Even animations and walkthroughs just show a small number of frames per second of relatively simple graphics. Gaming requires up to 100 frames per second of detailed graphics. The myth about graphics cards with CAD goes back to the old days of computers in the 286 class when we ran cards with their own memory and display list drivers to speed up panning and zooming on the screen.