Apple TV - not receiving good press on the NGs. It's basically a
strangled video interface.

Sad to hear. It seems pretty limited, particularly in having to link it
into iTunes rather than simply scanning SMB shares... Maybe someone
will reverse engineer it, ala mt-daapd.

I've transferred all my compressed music (80-odd gig) to a Mac Mini.
Issues/compromise/things include:

Sounds like a good start

D/A conversion - I'm not completely convinced by the Mac's ability here,
so I use the Mac digital output to a Cambridge DAC;

Using an external DAC seems quite inevitable, though I have heard good
things about the terratec range of sound cards. Still wouldn't trust
digital to analogue conversion inside a computer!

Incidently, I've heard that the digital output from a mac mini is
somewhat weak - though I don't know how noticable this would be, or
indeed if this is "audiophile speak". The Exposure 2010 CD player has
an option to turn off the LCD display to improve sound quality. Go
figure...

Monitor required - I use the telly. This might rule it out for you. I'd
just say that trying to access one of several thousand tracks on a 3
line LED using a remote is not pleasant;

I imagine I'll upgrade to a 42'' 1080p LCD soon - which could easily be
driven from PC.

Thanks for the suggestions.