I sometimes fall asleep with a song or playlist on repeat and will wake up with hundreds of plays which were acquired dishonestly, so I don't give much weight to play counts.

Same here, I left my iPod playing a full day at school, and sometimes, my scrobbler ****s up and scrobbles the same track 3 or 4 times. It still gives a rough estimate to what I listen to, which is always nice.

This is why I reset my play count every so often.