Graphic card

hello all,
i m planning to equip myself with a tower in XP, to use strongly vvvv.
until now I was more ATI for my laptop.
but if I well understood a good graphic card with a good GPU is needed.
I intend to work more on 2D, shaders, and video than making pure 3D.

8800 GT 512 Mo ?
NVIDIA Quadro FX 5600 ?
ATI Radeon HD 2600 XT ?