This is the dataset I used for ISMIR 2012 paper "Evaluation of Musical Features for Emotion Classification"

It contains 3 parts,
1. The top tags returned by last.fm (four emotion classes: happy, sad, angry, and relax)
2. A list of songs labelled with the retrieved from part 1
3. The fetched song titles that we used in this paper (due to the copyright, we didn't upload preview files)

Queen Mary University of London
Centre for Digital Music
Yading Song
yading.song@eecs.qmul.ac.uk