FOLLOW UP:

Finished the valve adjustment -- noise is gone; so for future reference what you're hearing in my initial clip is a valve that's too loose.

Changed rotor, cap, spark plugs (had to adjust the gap on one.) Also discovered slack in my throttle linkage, adjusted it -- car feels great now.

Bought a compression gauge but with all the talk of proper torque w/new vs. old washers and stripping the threads and carbon getting into the cylinder, etc. figure I best leave that to a professional. I've been meaning to have someone give it a once over anyway.

Thanks for the recommendations on that mechanic's stethoscope -- excellent tool. Heard a slight couple ticks after my first pass, the stethoscope told me exactly which valves I'd left too loose. And thanks to everyone who commented.

Random questions/observations:
How the heck do you guys fit a torque wrench on that #6 spark plug?
Loctite those feeler gauge nuts! Searching for the lost nut (eventually found) was not pleasant.