I've been running my Squeezebox since about the first of the year. I have about 10k songs on a external hard drive hooked up to my Mac. They use roughly 200Gb of space. I use iTunes on the computer but Slimserver for playing them through the Squeezebox.

The SB is connected to the Mac wirelessly and whether I am streaming internet stations or my own music, I have yet to notice a hiccup in performance.

And "oh by the way....." my output to my 990 is via the optical connection.

(now to finish ripping the remaining 700 or so cd's I have!)