What is the best DAC for under $200?

[Dom de B]

I'm looking for:
- The highest Clarity (most neutral sound)
- Just a DAC, I'm going to be using an O2 DIY amp along side it
- It can be DIY
- It MUST be USB compatible
- I would prefer a standard 1/4" unbalanced output
 
Thanks in advance, Dom
 
PS This is to be used along side a pair of HE-500's most likely if that makes a difference
 
EDIT: Just saw this http://www.head-fi.org/t/532704/e-mu-0204-usb-damn-theyve-done-it-again-and-for-129  and it looks appropriate can anyone comment?