HamburgerBoy
Prowler
Killers, for me. The guitar sound changes from having a nice contrast at times (H's raw dirty sound against Dave's clean and pure sound when soloing on songs like Wrathchild, for example) but having them flow one into the other (Prodigal Son did it before and better than Powerslave, IMO) in other cases. Yet despite the differences at times, it never felt like two different albums at times. Then there's the clear bass and drumming as people have mentioned, and Paul's shrieks and screams pop in at just the right volume. The only real problem is that at times Paul is a bit too clear... for example, having to hear him gasping for breath at the end of Drifter.