I second Peter_s' opinion on the Benchmark vs. the MHDT DACs. The Benchmark is one of the most dynamic DACs in that price range. It is a little on the dry side, but in my tube system it is an excellent match. Get the USB or Pre version of the Benchmark - you have the added flexibility if you want to go for a PC based system down the road.
Another very dynamic DAC, I really liked is the John Wright modded Bitstream or Bidat.
Another very dynamic DAC, I really liked is the John Wright modded Bitstream or Bidat.