I thought everyone knew all the major compound lifts, more or less, and the fact that they're good value (for time and energy put in), etc.
I'd be interested to hear about which isolation lifts the people here consider essential (like curls, mentioned a couple of times upthread already), and why. But hey, in case that sounds like threadcrapping...
Squat, deadlift, bench press, row, overhead press, chinup... and some compound abdominal thing of choice. You could go a fair way with just those, I reckon.