Kim Thayil played solos on most songs, and some great ones. Jerry Cantrell is no virtuoso, but has the ability to play solos that are just PERFECT for the song (Them Bones). The Conner brother who played guitar on Screaming Trees did some very cool lead work, especially on their last two albuns. Nothing flashy, but very complimentary to the song. McCready (especially) and Gossard also played a lot of solos.
And PowerSlave, i can add Dimebag Darrell and Zakk Wylde who kept the soloing alive in metal/hard rock in the late 90's. I love James Murphy's work in Testament, too.