Megadeth, Black Sabbath
First matchup was hard, but Rust in Peace actually has no filler. Defenders has some weaker(ish) ongs that I still love (Love Bites and Eat Me Alive come to mind). The ending of Defenders is a bit disappointing as we all know. But those all time classics in Night Comes Down, THE SENTINEL, and Heads Are Gonna Roll more than make up for the price of admission.
On the flip side. Rust in Peace never lets up. Even the crowd decided weaker links in Poison is the Cure and Dawn Patrol still rock. In fact I love Dawn Patrol. Sometimes I just listen to that removed from the title track because it's that good of a stand alone song. I don't even need to speak of the high points because they've been discussed to death, but know I love Rust in Peace.