Currently 23,926 MP3s occupying 98.5 GB.
Growing by maybe 200 songs a month.
No "albums". All individual songs, hand picked.
I can't stand to listen to streaming audio or anything like Pandora or youtube playlists because I end up hearing stuff I don't want to hear at all or stuff that is commonplace. I've got some very specific musical preferences and the only way to stay within those preferences is to keep it on my hard drive and play directly from it.
I almost always play in "random" mode, so I never know which of the 24,000 songs I'm going to hear and there are no doubt many I have not heard in 5 years or more. But I like the anticipation of never knowing what is next.