Okay, so you've got your GPU squared away, but what good are great graphics without great audio to accompany it? No good at all.
Sleek Audio SA1 - $80
Known best for custom earbuds with "tunable acoustics," Sleek's latest pair is far cheaper than its other offerings. Priced for the mid-range market, the SA1s include the same wild acoustic tuning as the more expensive siblings, and anyone other than your audiophile friend shouldn't find much to complain about. Heck, there's even a Kleer wireless module available to cut the cord if you so choose.
V-Moda Vibe II - $120
We'd be remiss of our duties if we didn't include a set of earbuds that played nicely with Apple's iPhone, so if you've got a friend who loves Apple a little too much and needs a new set of buds, these are a solid option. The onboard button enables users to switch between calls and music with little effort, and the headphone's mic and call/music button control are compatible with all iPhone models (1G, 3G, 3GS), iPod nano (4th gen), iPod touch (2nd gen), iPod classic (120GB), MacBook, MacBook Pro, iMac and Mac Pro (2009 models), as well as with VOIP, Skype, iChat and other audio recording applications.
SteelSeries Siberia v2 - $116
Getting a sound card is obviously just half the problem. Getting a decent set of earphones, headphones, cans or earbuds is the other half--because you know good and well you can't blast the satellites when rocking out at 3AM. The Siberia v2 headset is a great mix of music and chat, enabling online gamers to experience great sound and chat easily with online opponents/team members. And hey, these are fairly wild looking too, so the design-minded gift recipients should be pleased.
Asus Xonar HDAV1.3 Slim - $150
There's one major exception to the rule we noted above. If you're building a specialized machine, such as an HTPC, audio is obviously far more important than with a standard gaming rig. Add in a Blu-ray drive, and things get even more complicated when it comes to getting true multi-channel audio out from a PC. This super slim sound card is designed to operate in cramped media PC enclosures and decode lossless audio formats such as Dolby's TrueHD and DTS-HD Master Audio. If your pal's looking to build an HTPC, you can't go wrong with this card.
Asus Xonar Essence STX PCIe - $175
By and large, the dedicated sound card is dying. Most motherboards now include support for multi-channel audio, leaving cash-strapped consumers with little reason to splurge on something that's already taken care of via an integrated module. This particular card, however, caters to those who only want the best. It promises cleaner audio, more outputs, more support for audio formats and more bells/whistles than you'll ever use. But remember, this is a gift, and there's no denying that someone special would love unwrapping this.