DVI vs VGA

Always on the lookout for the next upgrade, I'm considering looking at a dual-screen 17-19" arrangement, with dual DVI outputs and S-Video output on the video card.

Since most mid-range video cards have a combo VGA and DVI output, I'm wondering what (if any) advantages are offered by DVI outputs over their VGA counterparts.

It's times like these where HowStuffWorks has its benefits, but not as much detail as I'd like.

I'm also considering having an additional broadcast (TV) monitor affixed to one side of the setup for previewing video editing. While a $20 12" second-hand monitor would be the right price, I'll have to track down a BNC-S-Video converter.