Tough to pick one....
"The Spell Can't be Broken" - Metal Church has to be up there. Although, they were somewhere in between thrash and powermetal, that song was definitely on the thrash side. Great tune.
"Climbing the Walls" - Wrathchild America is also a big one for me. Those guys never made it very big, but that was a huge song for thrash metal.
"Seasons in the Abyss" - Slayer...... yeah by their standards it was a ballad, but that may be why it was so good, because until that point, we had never heard Slayer tone it down to that level and it worked for them. That song was great !!
"Shattered" - Pantera.... hard to pick one song from CFH because there were many killer tracks.
"Nice Dreams" - Powermad..... well since I picked a thrash song from a powermetal band, I might as well pick a powermetal song from a thrash band. This wasn't as heavy as many other tracks from Powermad, but I think it was their best song.
"Lucretia" - Megadeth.... hard to choose a song from Dave and the boyz, but I really dig this one.
"Dyer's Eve" - Metallica..... this song is heavy and fast. I wish they had more songs like that after that release.
"In Search of Sanity" - Onslaught. Although I really only dug two songs from that release, that was one cool song. Steve Grimmett was one hell of a singer.
Bryant