There's a lot of options for what you are wanting to do, are you going to use the headphones for music too ? A dedicated sound card will always sound better than a single chip option mother boards come with. What kind of budget are you shooting for ? There are some pretty good headphones under $100, like the Monoprice 8323 ($21.59) Asus has the Xonar family of sound cards, they have excellent specs, and pretty popular option. If you can, demo as many headphones as you can. Do you need sealed headphones, is it noisy where you are, or others close you don't want to disturb ? Open back headphones tend to have better sound, but don't isolate well. Like I said, lots of options.