EDIT: Quite unfortunately, I'm not located in the USA or Canada, so I'm out of the game.
Anyway, good luck to you guys! The prizes are really great this time.
Well, personally, I'm a bit of an audioholic so I listen to music on a Xonar DX with a pair of AKG K324P headphones (I know, I know, maybe not the best headphones around, but they're quite good to be honest). The Xonar really makes the music come alive, unlike many creative and especially
any onboard sound card the I've tried. I first considered it after reading the review on TR comparing it to the D2X. It's by far the best audio card in terms of price/quality (drivers, features, overall sound quality). It simply gave me a better experience than the creative card it replaced ever did. I loved it immediately and still do, so if I have to recommend a card to anyone, it's going to be a Xonar, no doubt. Hey, I'm not trying to sound like an Asus commercial or anything, it's simply that my experience with their cards has been great. Yeah, sure, they have the "downside" of not supporting EAX natively, but they emulate it in software, and frankly, EAX is not in my priorities at all. I don't game that often, and since I use stereo headhones anyway, it's even less important to have EAX.
As for the HTPC, it's sound is handled by an X-Fi Xtreme audio (rebranded Audigy, I know, and it's not that good of a card, so I'm looking for a Xonar replacement) and Logitech X-540 speakers, which, actually, are quite good for their money, especially because of the Matrix feature to split stereo sound to all satellites, since they double as my TV speakers (I just couldn't stand the integrated ones in my Samsung LCD, they're probably the most tinny-sounding speakers I've ever heard). So that's all, I think.