Absolute top tier DAC for standard res Redbook CD

Hi All.

Putting together a reference level system.
My Source is predominantly standard 16/44 played from a MacMini using iTunes and Amarra. Some of my music is purchased from iTunes and the rest is ripped from standard CD's.
For my tastes in music, my high def catalogues are still limited; so Redbook 16/44 will be my primary source for quite some time.

I'm not spending DCS or MSB money. But $15-20k retail is not out of the question.

Upsampling vs non-upsampling?
USB input vs SPDIF?

All opinions welcome.

And I know I need to hear them, but getting these ultra $$$ DAC's into your house for an audition ain't easy.

Looking for musical, emotional, engaging, accurate , with great dimension. Not looking for analytical and sterile.
Steven Alex, on your respective DACs, what signal processing parameters can be controlled by user selectable settings on front panel / remote? E.g...

* Upsampling rates,
* Filter types and subtypes,
* filters on/off,
:* Other?

Saluti, Guido
This is directed to Randy....did you find the Signature upgrade on your Romulus to be worthwhile for playing Redbook? Also, do you think the transport in the unit is up to the quality of the DAC? Would it make sense to use a dedicated transport, i.e. Levinson 31.5, with the Pandora Signature DAC rather than go for the Romulus Sig player? I know the transport only adds 1K to the price so it seems like a worthwhile "risk".
Having recently compared the Aesthetix Pandora Signature, PSA DS and Berkeley Alpha Series II, I agree with Randy that the Aesthetix DAC is sublime and a hand picked set of of Gold Lion tubes adds to the enjoyment.
I was told the Romulus transport is a TEAC but not one of the best as installed in the top Esoterics.
IMO: It would be tough to beat the interface between transport and DAC in the Romulus with a separate transport and cable. I'll give it a try with my Wadia 270SE.
BTW: I had Aethetix replace the RCA digital-in with a bnc which they gladly did.
Reading this thread has been very interesting, but I do wonder whether a Mac Mini, even if upgraded for audio, is an optimal digital source. Also, I have found that there is often an interaction between source and DAC that can makes the combo either much better or much worse than the sum of the parts. For example, the PW Transport sounds great with the PW DAC, but lousy when used with my Behold Gentle G192 DAC/integrated. The Bel Canto CD3t sounds phenomenal with the Behold, but mediocre with the PW DAC. The best digital source I have had in my system, a demo of the LauferTeknik Memory Player, trumped everything else I have tried. In my experience the digital source can matter as much and sometimes more than the DAC. So, this thread may be quite useful for Mac Mini users, but may not be universally applicable. Of course, Matt has made it clear that his views are one man's opinion. But I guess I would be hesitant to conclude that the ODSE is the best DAC...it may just sound best with Matt's particular source.