This is fantastic. I've got two samplers that I've just started building a sample library for (Korg Drumlogue and Teenage Engineering's KO II) This is exactly the kind of tool that will help me find interesting sounds. Great job.
Even better, while there's plenty of music to be had, there's a lot of other stuff as well. In my case, what led me to even find this was just looking for public domain audio files I could use for testing and debugging various bits of audio processing software that I'm working with.
I'll be interested in maybe using some files for testing speech recognition and what-not as part of that. So some of the interviews and spoken word recordings will be of primary interest to me.
That said, I'm sure there's some interesting music mixed in here as well and I'm looking forward to exploring that. :-)