the combination of "starfire" and "two-step" on low's secret name record is one of my favorite musical one-two punches.
some other good ones:
"root down" and "sabotage" on the beastie boys' ill communication
"wreck of the old '97" and "i walk the line" on johnny cash at san quentin
"communication breakdown" and "i can't quit you babe" on led zeppelin
"lullaby" and "fascination street" on the cure's disintegration
of course i know there's other gooder ones, but i can't think of them right now.
what are your favorites?