DV is for a flatscreen digital monitor, which will set you back about $500 for a 15" (I'm not 100% certain, it's rarely used nowadays and I got my info second hand, so keep that in mind).
Don't ask me to explain how it works, but it doesn't depend on the RAMDAC to create frames, but rather sends a full digital signal to the flatscreen, and it descrambles it there to give the crisp image (I think).
The flatscreens are slowing coming down in price, I'd wait another year to get one. Of course by then you'll have (to get

) a geforce 3 which, already, comes with DV on 50% of the geforce 3 cards made today.