Every headbanger has heard of the 4 great German thrash bands: Kreator, Destruction, Tankard, and Sodom. Less known is the American thrash band Morbid Saint, which simply kills these four in quality and heaviness. Their only album, Spectrum of Death, is probably the best thrash album of 1988. The vocals and music are similar to the German guys most people are familiar with, except heavier, harsher, and better. The drumming is good enough to be in death metal. Perhaps the Eddie rip off album cover drove people off, which is a real shame, since they're nothing like Iron Maiden.
Along with Blind Illusion, this is probably the most underrated thrash band of all time, given the quality of its music. They're better than Armoured Saint and Morbid Angel put togther. Well, maybe not, but they're still amazing.