About 15000 I guess. Spread on about 130 cds. MP3s make me buy more albums though. I found out about Opeth through mp3s and bought all albums instantly.
Probably about 100 at any given time - it flucuates when I buy albums then delete all those MP3's, burn the occaisional CD of mixed crap (this has only happened once or twice, tho), or really need some disc space.
None
my computer has got no sound...in my time of glory i had over 2000 in hdd and cds of mp3 but sadly i owned 3 originals of the 200+cds i had in mp3 ( 2 dt's and 1 inflames )