what is the best, least costly DAC...?

I second MF V-DAC. Astonishing value @ $299. Even better with the outboard power supply (Little Pinky, MF own V-PSU etc).

V-DAC does 24/96 but is limited to 16/48 on the USB input so you would have to invest into M2Tech hiFace Asynchronous USB To S/PDIF Converter ($150) to be able to play hi-res files.

I bought one for my sat box, but put it one day in my hi-man rig against dCS Puccini, and to say that I was amazed by this little DAC would be an understatement - I was amazed.

Cannot recommend it highly enough. The outboard power supply of some kind is mandatory IMO.

Kbarkamian - V-DAC is ANYTHING but dull and lifeless sounding. It is very transparent, with excellent resolution and soundstaging.

If you found it dull sounding, than it may be one of two things:
- your DAC was faulty
- your system was voiced around old Theta gear, which is known to be very bright and brittle sounding. I know Thetas very well, since I owned a dosen of their dacs: Cobalt, Prime II/IIa, Basic II/III/IIIa and Gen V/Va/Va balanced.

Here is an excelent review from hifi critic:

http://rapidshare.com/#!download|266|422349120|MF_V-DAC_HiFi_Critic.pdf|9181

and German AUDIO:

http://www.taurus-high-end.de/infomaterial/cambridgeaudio/test/test_dacmagic_audio0109.pdf

Wait till you hear it with an upgraded PS ! It makes a big difference.

That beeing said, I have just found another DAC, which has all the rights to became a classic - it is Arcam rDAC. It is 50% more than the V-DAC (without the upgraded PSU) but sounds much better than the mighty V-DAC. It actually sounds even better than the V-DAC with the outboard PSU, which pricewise puts this DACs in the direct competition.

The rDAC sounds very fluent, analogue like with a nice texture, and offers a trully AMAZING resolution. HF decays, spatial clues, HF smoothness - the dac sounds so real that it is scary. And that comes from a dCS Puccini CDP owner no less !

The icing on the cake is asynchronous USB 24/96 input with dCS licensed technology !

Stanwal has a point.

I'm using my V-DAC right now in my hi-man system - Wilson Sasha -> darTZeel amp -> Kondo M1000mk2 preamp - and it sounds great. You need to invest in a better PSU though.