In no particular order:
Randy - his leads still amaze me 20+ years later.
Gary/Rick (Exodus) - great tandem
Frank/Tommy (Tesla) - another great tandem
Denner/Sherman (Mercyful Fate Dont Break the Oath/Melissa era) - yet another favorite of mine
Eric/Alex (Testamant) - nuff said
Hetfield (KEA, RTL, MOP, AJFA) - those early albums were awesome!
Dime - dudes riffs were great!
Scott Ian (Among The Living/Speak English or Die) - those two albums are two of my favorites
Dave/Adrian (Killers thru Powerslave era) - many many great memories from seeing them back in the day
Jeff/Kerry - SLLAAAYYYEERRRRrr
Mark Reale (Riot) (Guy Speranza / Rock City, Narita, Fire Down Under era - awesome tunes
Schenker (UFO era) - that is one of my all time favorite bands ever. I was listening to a compilation cd of UFO that I made the other day and that Schenker era of UFO was one of the best bands ever!!!