Entertaining / funny:

-Fear and Loathing in Las Vegas (Hunter S. Thompson; Criterion)
-This is Spinal Tap
-Blood Simple
-Apatow and cast commentaries (especially 40 YOV)
-Kevin Smith (funnier than his movies)
-Herzog
-Men in Black (Sonnenfeld and Jones)




Insightful / informative commentaries:

-Straw Dogs (Criterion)
-Citizen Kane (Ebert not Bogdanovich)
-All three Godfathers (Coppola; the third made me see what his intentions were; upgrades the film from outright awful to really bad)
-Dark City (Ebert)
-Dazed and Confused (Criterion)
-Herzog (especially Fitzcarraldo)
-Killer of Sheep
-If... (Criterion)
-Rules of the Game (Criterion)
-L'avventura (Criterion)
-Autumn Afternoon (Criterion)
-Alexander Nevsky (Criterion)


To pick one from each: Thompson on Fear and Loathing in Las Vegas and Prince on Straw Dogs. Listen to them ASAP.