Angel of Death by Slayer has a mind-blowing solo. The solo for Highway Star by Deep Purple is nice. Epic by Faith No More. The name says it all. The entire Killing is my Business album by Megadeth (and Peace sells off the record of the same name). Alive by Pearl Jam has a pretty good solo.
If you want ridiculously hard solos listen to annihilator. I'd recommend Downright Dominate, Operation Annihilation, Army of One, and Clown Parade. You can also throw in Demon Dance