Audiophiles out there? HELP

I would recommend the ODAC by Nwavguy. It is one of the best from the DIY community and measures impeccably. You can get it from a few vendors around the world, including JDSLabs. I have 4 of these for different places. The important thing is that this DAC measures well and thus is extremely transparent and clean.

My other suggestion would be a DACPort, from Centrance. I have that little USB DAC/headphone amp as well, and it is my reference level gear. Compared to it, the ODAC is indistinguishable to my ears, so that's why I would recommend the ODAC. If you want to drive headphones too, you would ideally want a combo -> O2 (amplifier)+ODAC (USB DAC). They come in the same enclosure, if you want that too!

See http://www.jdslabs.com/item.php?fetchitem=48

I have thus far tried the following:

DACPort (terrific, just great and analog-like smooth sound)
ODAC (just as good as the DACPort, but cheaper if you don't need the amplifier, plus a lot of fun building O2s)
EMU USB 0202/0404 (they were okay, a lot of modding fun)
M-Audio Audiophile USB (meh)
Zhaolu DAC (it was okay, modding fun too)
Pico USB DAC (meh)
Beresford DAC (meh)
GrubDAC USB (cheap DIY fun, not that great sounding)
Audial NOS DAC with USB (sounded okay)
Creative X-Fi Xtreme Music (came with a computer, I then modded it, sounded okay)
+ some other things I can't remember.....

Over all, I sold everything except for the ODAC+DACPort. Those two sounded absolutely the best to my ears. The ODAC is only 100 bucks or so, but if you need to drive headphones, you should go for the O2+ODAC combo.

As for a pair of headphones, it really depends on what type of sound signature you would like. The Sennheiser HD5xx to HD6xx series have an airy, neutral sound that some may find a bit boring for music like rock and roll and vocal heavy stuff. The Grados are fairly mid-centric. The Beyerdynamics are great too, but sometimes relies on special amplification (due to impedance and bass response). There are also Audio Technicas, AKGs, etc...

Those are all "reputable" brands. As for the sound, you really MUST go to a dedicated audio store or pro-audio store (recording music-audio) and try some to find out for yourself, and the music you play (bring it with you). You don't have to buy the equipment there, infact, you can get much better deals online.

So for headphones, they basically break down into 2 large categories, not including the in-ear stuff. You have the closed back headphones and open back headphones. The open ones (like the airy sounding Sennheisers) have a much more spacious, open sound that some enjoy because they are similar to being in a concert hall or using speakers. The closed ones (like quite a few Beyers), are more suitable for electronic music where there isn't a lot of ambiance or doesn't require a lot of that. The bass region is typically more powerful on the closed back headphones, because of the chamber loading, but as a trade off, they are not as clean sounding and can get muddy. Then there are sometimes hybrid types, which are really open back designs with a small foil or small slits to let some back wave out, in an attempt to be some where in between the two sound signatures.

Again, you really need to listen to them to see what they are all about. But a general rule, if you hate headphones's effects on the music because they make the music sound like more in your head, you probably won't like the closed back headphones (there are exceptions). If you love bass and don't care for spacial cues, you probably would like the closed back headphones.