Jeno’s Pizza Rolls ad by Freberg. That’s his voice doing the closing “Hi-yo, Pizza Rolls!”
Here’s the Freberg prune ad with Ray Bradbury. http://www.youtube.com/watch?v=A5NxG_rr5aU
The Detroit Zoo ad was funny.
I love these! Every time I try and single out one of them to be proclaimed the best of the three, the others present a strong case for themselves.
I think “sucking” is the least good of the three and the other two are tied.
Oh, shnap! 
An oldie, but a goodie:
The gorilla playing drums of course
Wanna Learn English?
NSFW!! NSFW!!! NSFW!!!
That reminded me of this one. (SFW but strong innuendo).
Have you seen this out-take?
Red Rock cider (Naked Gun style ads)
There was at least one other in the series, but I can’t find it on Youtube. It had Hank Marvin in it.
Boy, that Police Squad theme sure is catchy–I’ll be humming it all day, curse you! 
Any “best commercial” thread has to include the “In an ABSOLUT World” pillow fight ad.
One my all time favorites.
Beer commercials have always been among the best.
Mickey Rooney’s series for Rainier beer.
Dude, that was Dailykos. Unless there’s a secret link somewhere, I think you meant to link here.
That’ll teach me to have 4 windows open at once. :smack:
My favorite growing up, it’s for a now-defunct local electronics store, Highland Appliance.
“Once again, Ricky Dee!” My 10-year-old self would roll on the floor at the pants rip every time.
One of my favorite car commercials ever (Peugeot 206)
That’s it - thank you! Jeez, who is that?
I love “Tolerate Mornings” from Folgers (AKA Happy Morning), however, this is just as good and I don’t know if anyone has mentioned it yet: