What's perhaps more interesting about MTV, than their first day, is the list of videos they played ad-nauseum. I remember one summer (1990?) when it seemed every third video they played was Queensryche's Silent Lucidity. Great tune, the first 3 times you hear it, but you're subjected to it 4 times per hour for 4 months, it really loses its luster.
The first of these, "please kill me if I hear it again" MTV music videos was "Hey Mickey" by Toni Basil. "Relax" from Frankie Goes to Hollywood, "I'm so sexy" from Right Said Fred, "Gonna make you sweat (Everybody dance now)" from C+C Music Factory, the symphonic derailment from Metallica, "Groove is in the heart" from Dee Lite. MC Hammer? Who else?