For the better part of the last 5 months, I've been putting a 2,000 song mix together for my mp3 player. Adding, subtracting, organizing, and compiling into a flowing work. These are now done (though the last 500 aren't typed out) compiled over 4 playlists (as my mp3 player will only do 999 song lists - who knew?). I've chosen this length for that and since each of the playlists begins with a version of The Pixies' "Where Is My Mind."
In compiling the rules for this, I've decided that an artist can only be in 1% of the songs, though if said artist appears solo instead of with a band or said person is featured on another person's song, that's different. For instance Ben Folds and Ben Folds Five and Ben Folds with Nick Hornby are 3 different entities.
1st 500 Song List (1-500)
3rd 500 Song List (1001-1500)