I like Robb Wolf's approach. Every time he goes into the gym he does a push, a pull, a squat, and a hinge. So I'll generally do either flat/incline bench or shoulder press for my push...rows, lats, or pullups for pull...squats or lunges...and then kettlebell swings or deadlift (latter checks both the squat and hinge component).

Out of the gym in 20-30 minutes and in better shape than I've ever been (and I've lifted since middle school football and now 55 yrs old).