35 Songs
I've published my "35 Great Songs" list to the iTunes Music Store. However, I managed to pick artists obscure enough that only 16 of them are carried in the Music Store. To find the list, search for "16 of 35 Great Songs" under the user name of "Tanukitaro."
My next project is to assemble the digital tracks of a mix tape that friend gave me a few years ago. Hmm. "Bearing Witness," I have that. Now where's the tape so I can replicate the list....

UPDATE: The Flash Girls "Signal to Noise" is not on Limewire. Their CD is available but I don't feel like spending a sawbuck to get one song. I am cursed with needing to find obscure music.