DAC choice advice - hard-drive based system

Putting together a system using network-attached USB hard drive (LaCie 500GB through a Linksys NSLU2), all music ripped lossless (FLAC), delivered over my 802.11g wireless net using a Squeezebox3.

In the general price range I'm considering, the Audiomirror, Perpetual Tech, Stello, and (it seems you can't *not* consider this) the Benchmark, all look interesting. I realize the Audiomirror takes a different approach as it's n/os.

I listen to a very wide variety of music.

Can you guys help me out with the pro's and con's of these options? I'm new to the DAC concept - am I missing anything I should be considering?

Also, what is the concept behind something like the Perpetual Tech P-1A? I don't really understand what it does (but have a general sense of the concept of oversampling). Is it just oversampling, similar to what's already built into the Benchmark for instance? How about the Audio Alchemy stuff, what's that do?

Thanks! Great forum, it's nice to have access to experts that don't mind speaking in language plain enough for us neophytes...