Headphone Rig for PC?

I just downloaded some 24/96 albums from HDtracks and am thinking about the possibility of a nice headphone setup to play them and others off my PC. I am new to this, so what exactly am I going to need, and does anyone have any Sub-$1000 system suggestions? I am running a Vista OS.

All you need is a good dac and a headphone amp or a dac with a built in headphone amp.

Benchmark Dac 1 with USB is perfect for you because it also have a very good headphone jack. I used it with Sennheiser 650 cans and the sound was excellent. A used Benchmark might come in under $1000. THere are probably other brands with headphone jacks and USB for less money.
Dennis is right. Of course in this hobby you can always spend more money if you wish, but I think the Benchmark is an excellent solution with a PC.

Have fun!
That's kind of where I was leaning but I wasn't sure if an additional headphone amp would be necessary. How about the digital connection? I have a silver serpent digital coax, will that suffice?
I'd just run USB straight to the dac if I were you.
Any significant differences in USB cables?
Kimber makes a great USB cable for about $50. You'll have to spend substantially more ($400) to get much better.
thanks for the help everyone