My current recommendation would be to get a pair of good headphones (I have the Sennheiser pmx-100, which are less "good" and more "decent but portable" as I use a laptop), and purchase a mic (not USB) separately. You'll get much better performance. Currently, you can get the 64-ohm version of the Sennheiser HD280 pro off of eBay, for about $65 shipped (eBay store Dakmart is selling a bunch of them in buy-it-now sales). This is an excellent deal on a good pair of headphones with an MSRP of $199. An alternative would be to jump on the $80 Grado SR60i's, which are widely regarded as the best headphones under $100.
A mic would cost anywhere from $5 to $20 additional, depending on where you got it from. on eBay, you can get cheapo mics from China, that consist of a gooseneck boom separating a 90-degree 3.5mm minijack and a microphone element. That combined with a paperclip and a 3.5mm m/f extension cord would get you an excellent "headset". Though, as a word of caution, the mics do take forever to ship. I ordered a few different ones, and the first to arrive took 10 days, while I still haven't received the last one (almost a month and a half and they still say, "they're coming")
As for headsets, I currently have Creative's Fatal1ty headset, and it is pretty good. The only issue I have, is that they are extremely bass heavy, but it is nothing an equalizer couldn't fix. They have excellent THD performance, meaning that you should be fine even at loud volumes using equalization. Otherwise, the mic is really good, though I would recommend not unplugging it from the headset, ever. A lot of people have had issues with the mic breaking, and they don't make replacements. Apparently, the removable mic is a badly executed gimmick from Creative.
A band-aid fix would be to jump on the $16 Plantronics .Audio 510 (USB version, thereby not utilizing your fancy soundcard) from Buy.com, and they also have the Barracuda for $65...if that changes the game at all. The 510 is a good headset. It has a very neutral sound, but it does distort kinda easily.
The SteelSeries 3h is another one I have, but is definitely a step down from the Creative offering. It's only a little cheaper than the Siberia, and while they have different drivers, I would be curious about how much the extra $15-$30 would get you.
On hearsay (pun unintended), I can tell you that the Steelseries 5h is geared towards the upper reaches of the sound-spectrum, and has very weak bass performance. I have the (now discontinued) Plantronics .Audio 370, and they embody everything negative I've heard about the 5h. The intent is that the frequencies that are pertinent to the directionality of sounds are emphasized, but you could do that with an equalizer. The only result is that music sounds flat and utterly unappealing through them. my $40 Sennheiser pmx-100 completely blows them out of the water in terms of sound quality, as do the $20 Koss KSC-75's.