Scott's vocals on the MTV Unplugged special and the Headbanger's Ball acoustic Plush. His voice was really showcased on those.
Dean's solos in Silvergun Superman, Trippin', and Lady Picture Show.
Robert's bass work in Big Empty and Lady Picture Show
Eric's drumming on Trippin', Big Empty, and Army Ants. I love Eric's drumming on Big Empty, very underrated, without it the song would be totally different.