USB/SPDIF converter and DAC combinations

I am currently using M2Tech Hiface with PS Audio DL 3. Will be looking to upgrade. Seeking opinions on the Bel Canto devices, Wired4Sound DACs, Audiophelio converter. What makes for a great combination and is this a better approach than USB conversion within the newer DACs? This question is asked within the context of a 15K-17K system retail. Thanks in advance for your replies.
I have no experience myself in USB/SPIF converters but:

I have seen more then one shoot-out between some converters. Maybe they are of some help.
Thanks Mordante. I have found this site after i posted this thread. I am considering the audiophellio2 and then upgrading my DAC.
IFi Audio a division or Abbington Music Research has just released the ILink. It is a USB/SPDIF coax and optical converter. The product is very new, but the whole Ifi line is getting great reviews and I'm sure the iLink will follow suit.
Don't let the prices fool you into thinking that they are cheep. Every piece performs well above it's price point.
I have the iPhono and couldn't be happier.

Good luck
I also have a DL III. My dream USB converter is an empirical audio offramp, my second choice is the JKSPDIF MK III, link here:
The reason I like the JKSPDIF unit is it's quite an elegant solution, it's battery powered, the power circuits are isolated from the audio section, and the battery re-charges from the USB port on your computer. No wall warts. I am currently running a Vlink 192, and I'm pretty happy. I wanted to get off the merry go round for a bit, so I'm taking a break from equipment purchases and just buying music. I have also looked at the audiophelio, and the anedio U2 unit.