Also check out Zakk Wylde's "Black Label Society" ,they've got a real agressive metal spirit with cool guitar and vocaling.
If you want to focus on shredding , why learn it from bands while you've got some realy great shreda$$ solo guitarists out there ?
Vai, Satch , Malmsteen ,Jason Becker , Michael Angelo , Paul Gilbert ... To name a few.
If you learn these solo stuff , any song for any band (excluding Dream Theater,Symphony X , and similar ones) would be a piece of cake.