What is the best used sub-$500 DAC?

I know the answer depends on many things, but I'd like to see how people respond without my particular preferences or system details/conditions. Thanks!
Museatex Bitstream.
Concur with the Museatex, but will also add the EAD DSP7000 Mk.III.
I'd pick up a used MHDT Paradisea or a buy pre-built Monica 2. Both are very organic.
I have a DAC-ah - around $220 new - 8 parallel chips - NOS (non oversampling - filterless). Plenty of good reviews and fans of it here. But then I have not heard a lot of DAC's except I can say it sounds a lot better richer, deeper soundstage than my source unit's built in processors.
Second the MHDT recommendation. I use the Renaissance II. Before that had a Heart CD tubed cdp and the Lite Audio DAC60.
I second Tonyptony's EAD DSP7000 Mk.III suggestion.

I tried out even the Musical Fidelityunit that Sterophile went all gooey about, and the EAD was much better.
I heartily recommend the Oritek-modded Zhalou at this price point. It's sins are mostly of omission (and it has very few, for this price). Gives up a little extension, dynamics and life compared to pricier models, but hangs with much more expensive pieces. It replaced a Modwright P3A and Consonance 120 in my system.
Thanks for all the responses. i'm usng a trends audio class t (TA 10.1) amplifier and a pair of tekton design 6 inch fostex full range speakers and plan to replace the amp with something low powered and single-ended. what about the venerable CAL Sigma? is it competitive anymore? thanks again for all the options...just what i needed.
Nhtran: How would you compare the sound of three units you mentioned? I am very curious, thanks.

A friend had the CAL sigma long time ago, without a jitter box it was not good.
Don't forget about modded Art DI/O's, which can be had for a song these days. Still a very competative DAC. Lots of detail and resolution and dynamics and very musical. Able to handle soft, sweet stuff and complex music with ease.

It is NOT an overly soft NOS sound, so if that is what you are looking for then look elsewhere, but I've found that NOS DAC's generally can't handle anything with punch or big dynamics or that is complex.

PC/MAC- Wirless/Wired - Squeezebox and modified powersupply and use it as a preamp ideally.

Once you go to computer streaming with your whole collection online you won't want to put a CD in your CDP. you can mod the Squeezebox as funds become more available.