Dude, the Portnoy and Petrucci vids...I used to have a looping feature on my VCR and would put them on repeat when I went to sleep. Same with Portnoy's Liquid Drum Theater videos. The Yngwie VHS I had a dub of that my uncle gave me when I first started playing, I never learned a thing from it because I'd just watch it as entertainment, that shit was like mythical at the time for me, I didn't think it were possible for another human to play like that.
I wore out 2 copies of Eric Johnson's Total Electric Guitar, too. That, I actually learned a lot from and it was essentially the cornerstone of my playing.
My best friend's dad owned a drum shop in Maine, (Mainely Drumz), when he got those Portnoy vids in we skipped school and spent the rest of the day watching them on repeat. I eventually got my own copies just to add to the growing pile of anything DT related I could get my hands on.