I love listening to my music library (cheap £500 10TB microserver) on continuous shuffle when Im back from a hard days work, it manages huge libraries effortless and plays music back instantly. My existing playlist is currently 6000-songs strong and counting.
FYI I use MM Gold. Tip for iPods, etc, you can configure non-compatible formats on the fly but make sure you manually choose stereo (Options> Portable/Audio Devices) as otherwise it will default to the lesser joint-stereo - worth sticking to 320kbps mp3 for connecting to car systems.
I make sure MM uses my SB Audigy soundcard for hardware acceleration and its crystal clear with no stuttering, even on 4500kbps 24bit/192KHz FLACs.