Latest thinking on my end: PC Link for USB>spdif @ 24bits >> Super Pro DAC in the box >> Trends Audio TA-10.1 Class T integrated amp
The Trends TA-10.1 and Super DAC can be bought as a combo for $198. So the whole setup will be about $250 for USB digital soundcard (to replace my aging AOpen Cobra card), 24-bit DAC, and Class T integrated amp.
Ok, just a follow up on this:
I did end up ordering the playback system above. I got the Trends Audio Class T amp and the Super DAC, still waiting on the PC link 24-bit USB soundcard. At the moment using my 16-bit Aopen card.
I haven't had a chance to listen to it much or break it in, but so far sounds very good for the price. Great detail from the Trends amp, and it has a very quiet/black background. I'm using it in my office system connected to a pair of Soliloquy Sat5 bookshelf speakers and a cheap sub (AR PR1010 or something like that). I've got splitters on the RCA outs of the Super DAC going to the sub and going to the Trends amp. Probably not the best set up, but all I can do. When I get a chance, I'll configure the Trends to be a straight amp, not an integrated with the volume knob active.
This provides amazing sound for such a tiny system. The really small footprint is just what I need, and when I re-arrange my office, I may just bury everything behind my desk.
Also, I should say that I am running the amp at the upper end of it's amp'ing ability. Mainly because I have pretty inefficient speakers. I think the Soliloquys only have a 87db efficiency. So for a desk top system that isn't meant to really crank, this works fine. Otherwise, for a main system, you probably want speakers with at least 93db efficiency.
The Trends T-amp is very good for what it is. Pretty incredible sound from a amp+DAC setup that is only $200 for the pair. I'm going to order a second setup for the living room playback system (leaving my family room with the primary playback system intact). I'm just trying to decide if I want the DAC as well for this system, or just the T-amp. Wall mounted "bookshelf" Monitor Audio Bronze 1 speakers, Trends T-amp, and the Squeezebox -- it'll be a nice 24-bit playback system for all my music in an overall footprint that will make the wife very, very happy.