Aim and Ignite by fun.
Somewhere in Time by Iron Maiden
Rust in Peace by Megadeth
Death Magnetic by Metallica
The Great Southern Trendkill by Pantera

And if we include EPs...

Voyage/Embrace by 2814
Fable by Vallis Alps

If I had to pick an absolute favorite, it'd be Fable. It's the closest one can get to a masterpiece, IMO.