Vacuum leak - how to find?

Hello all,

I'm under the impression that finding an automotove vacuum leak is a bit
of a black art and would appreciate hearing from experienced techs about
favored techniques.

I've heard of using a rubber tube or auto stethescope to listen for 
audible leaks, and some folks have advocated spraying various things 
around and listening for changes in engine performance/idle speed.  Have 
also read about a smoke test, which I think requires specialized 
equipment.  At the same time, I've read admonishments in manuals, TSB's, 
etc, that these techniques should NOT be used (solvents/smoke).

What do you do to find vacuum leaks?

Powell