The best sound-card for games: (only because of EAX do I recommend Creative)
Newegg.com - Creative 70SB046A00000 7.1 Channels 24-bit 192KHz PCI Interface Sound Blaster X-Fi XtremeGamer Fatal1ty Professional Series - Sound Cards
Another option: (better value option)
Newegg.com - Creative Sound Blaster SB0570 Audigy SE 7.1 Channels 24-bit 96KHz PCI Interface Sound Card - Sound Cards
All these sound cards do is output sound for headphones/speakers to use. I don't know much about amps and such, so I can't help you out there.
If you have the money go for the xfi.. but if your on a budget go for the audigy. In all honesty there isn't much of a difference... just a few more extra stuff here and there that won't really be necessary for what your planning on doing.
Ask that question about the amp in the audio related section..
Btw, you still need a sound card to get 7.1 surround output, unless of course you have an integrated sound card that outputs 7 channels already. But yeah, you will still need a home theater amp thingy