Not quite what you're looking for, but I use a pair of KOSS open-ear titanium driver headphones (~$20-40 depending if it's on sale) and absolutely love them. The sound response on these are always noticeably superior to cheap headphones or earbuds and even most average speakers. This includes bass and treble. I have a pair at home under the Radioshack brand but recently bought another pair for work which were sold under the KOSS brand.
as for sound cards, my SB Audigy2 ZS sounds very nice too, and I like the built in bass/treble boost 'cause it actually sounds good... doesn't clip the audio like software EQs usually do.
I think I've heard good things about those (if it's the model I'm thinking of). More pricey than an XFi though isn't it?
I still don't get what the difference is between a gamers sound card and a normal one. It's not like you get a free aimbot with the gamer's version.
I *think* it cost me about 130 dollars. In the grand scheme of recording technology, thats DIRT cheep. Comparing it to an XFi isnt fair because its not designed for the same purpose. And there in lies the difference between gaming cards and pro audio cards. The pro audio cards contain no hardware dedicated to creating special audio effects for in game audio. And they're usually not able to decode high def audio and DVD movie audio codecs. Traditionally, gaming cards were sonically inferior to pro audio cards because gamers and nearly all computer users were people who didnt care about high fidelity audio.
Thats changed for the most part and you can get gaming sound cards with fantastic tech specs and fantastic quality. Although, they are still lacking in recording capabilities, but thats to be expected. Most people dont need to record anything period, let alone record and mix multiple channels at once.