I agree about Delirious. My friends and I could quote it pretty much word-for-word back in High School.

However, for single performances, I'd go with Bill Cosby-Himself. I think it is amazingly funny, and I personally add points for him cursing only once in the whole thing. Also, I still use a number of lines from Himself--"Daddy's great, give us the chocolate cake" and "I hobep that you are sabisfibed" (the latter from the dentist bit).