The squeezebox3 was actually the next gadget on my list to purchase... the 770 got bumped up when it was released unexpectedly (there's also a backlog of orders for the black SB3).

The SlimServer and SB3 combo seems to be the best of breed music playing software out there right now. SlimServer is OSS and you can write plugins for it... it's generally a good match with the 770's platform for your home entertainment needs