Sound cards that work well with headphones?

Hello, I don't know much about sounds so some advice from you pros will be very appreciated : )

My parents don't like it when turn up the speakers for pc games, mp3s, and Divx movies... so for the past few years I've been using headphones on my computer.

My current rig consists of Sound Blaster AWE 64 plugged into a Pioneer XC-P410T receiver (bought it 10 years ago), and I use the headphone directly from the receiver.

I'll probably be getting a new computer soon and I'm wondering which sound card works well with headphones. The headphone I've been using is just a $50 CDN Koss TD/65 I bought off some tech shop a few years ago. I don't think I'll use this headphone for the new sound card.

So, which sound card and headphone would you recommend? I will use the sound card and headphone for:

1. Listening to mp3s on comp or CD from stereo
2. Watching VCDs, Divx movies, DVDs on the computer.
3. Playing 3d-shooter PC games.

I heard that Game Theater XP is good for headphones, but I've no idea what headphone I should get. Wireless headphones would be nice but people say their sound quality is bad and I don't think the price is within my budget.