Others who went to Helix High (my HS): Dennis Hopper and basketball star Bill Walton.
Here's a fascinating story by Bart Mendoza on Hopper, Zappa, and Morrison's stints in SD:
When I was a kid I had a friend who's uncle or cousin (can't remember now) was in the band Gary Puckett and the Union Gap (his name is Gary "Mutha" Withem). They got their start in SD.
Didn't Iron Butterfly start here? And the great band The Lyrics ("So What?"). What other bands did?
Mojo Nixon was pretty famous for a while - on MTV and all.