Graphic/video card why?

Ok been using store bought computers for years. Currently building my own machine and overclocking for the first time. I want a very fast machine.(compared to a dell with a pentium d 945)

p5nd2-sli - modo
Pentium d 945 - will get C2D soon, practicing on this one
20 crt sony trinitron

Im not a gamer, i am a web/graphic designer.
I run alot of programs at once like adobe suite.
Large file sizes when working with photos.
some vedio editing, lots of Flash

So what is the real point for a rather expensive graphics card?

Is it better for me to get 2 ati x1650 or 1 x1950?
I like the idea of 1gb of ram but cant afford 2x1950
Ive used ati a ot and have been happy, but im fine with the 7600 if you all think it is better.

My main concern is what effect will the better cards have on my computer. If I wont see a difference the why spend the money?

thanks, that is what i figured.

I do very little 3dmax work, and as long as the card supports open gl Im fine in max with the card i have. (radeon x600)

so would two cheap 512 cards be better since i would have 1gb available or would the computer not really know how to use it?

cool, that saves alot of money and power

thanks abunch

my old mans machine had integrated graphics (intel 865g), the xp fade effects would skip and web pages with flash, the sound would go out of sync with the video and little things like that - i chucked in an old TNT2 M64 AGP video card and that worked wonders so integrated grapphics - my preference is a cheap video card from ATi or Nvidia.