Ride the Lightning is the one Metallica album that seriously has a lot of aggressive power and remains a classic to this day.  While I'm not particularly thrilled with a few moments here and there, overall it's much better than what many of the metal bands in the mid 80's were doing (with all their big hair, constant partying and chicks).  Metallica's music remains fresh and exciting all these years later.  This album was REALLY underrated back in the mid 80's.  People back then didn't know how to approach something with this much speed and punch.