Slightly over budget, but my definite suggestion is the Audio-GD NFB-12. It costs $200 without shipping, although there is currently a 5% off ($10) due to an anniversary.
It is definitely the best DAC/AMP combo out there for $200.
I have it myself, and I think it's worth the $200 even if you use it as a DAC only, and you'll find that many head-fiers agree with me.
Another suggestion is the famous Fiio E7/E9 combo. The combo also costs around $200, but from what I've heard the NFB-12 is slightly better.
Take this with a pinch of salt though, since I have never heard the Fiio combo. You'd better ask someone who has heard both.
If you have a tight budget the cheapest option would be the Nuforce UDAC-2. At $130 street price it is fairly cheap, although many claim it to be a good amp/DAC.
This one also has as an advantage that it's portable, whereas the Fiio and NFB-12 is less portable.