If you like SlimServer, check out Ampache (open source, Apache/MySQL/PHP server at www.ampache.org). Based on the last time I tried SS, I like Ampache's interface much better as well as the high level of tweakability. Its actively supported with a pretty good user base. Oh and it supports localplay through MPD, moosic, etc. I believe its also working with boxes like the slimp3 and the squeezebox.
When I (finally!) order/get my 770, I'll be writing a 800x480 user interface to Ampache.