Total Bithead is a pretty darn awesome USB DAC plus headphone amp. $150 might seem expensive, but if you get good headphones, and you do some A/B comparisons, you should easily be able to hear the improvement. (If not, send it back, and they'll refund you.) There's $30 DAC/amps on eBay, but it's hard to tell if you're going to get a bargain or a rock in a box. These days, I'm betting the latter. Headphones: If you need to block out outside noise, and don't want to spend a huge amount of money, there are three awesome choices: 1) Beyerdynamic DT770 -- under $200 street price. Conventional over-the-ear headphones which are comfy and sound awesome. Coupled with a good audio source and quality music, you will listen to your favorite song and say, "I never knew there was a guy playing mandolin on that track!" (Absolutely true story.) To get better sound, you pretty much have to go to "open" headphones (which don't block as much outside noise) AND pay more. 2) Fidelity Custom Earphones -- about $300 ($250 plus an audiologist fee to get ear molds taken) They go in your ear canals, but because they are custom-fit, you can sleep in them. (I have, many times.) Sound is, as the snobs say, "detailed" and "neutral." In other words, if you want to listen to string quartets, they work great. And if you want to listen to dubcore, maybe add a little bass boost. 3) Etymotic 6i or MC5 -- well under $100. These go in your ear canals, and are not custom-fit, so you have to push them well in, and you'll want to take them out every hour or so. On the upside, there is NO better sound for the price. In fact, it's hard to find sound even REMOTELY this good for two or three times the price.