I was 5 in 1990, but do remember some songs I used to like:

Richard Marx: Take this heart (Chicago Cubs, good vid!)
http://www.youtube.com/watch?v=7WLZ4iPHkm0

TLC: Baby baby baby (i had the biggest crush on T-boz and especially Chili!) got to watch just for the crazy styles!
http://youtube.com/watch?v=VrnBBNY5PuM
Of course, MC Hammer
http://youtube.com/watch?v=EMzoBkaFxh4
And Marky Mark (i cant believe he had a future after this)
http://youtube.com/watch?v=UnzgNAzquCw