Lots of good ones mentioned.
The SmartBeep Blind Date commercial always makes the lists:
http://www.youtube.com/watch?v=epjrWjo9ZMY
I grew to like the Budweiser “Whassup” commercials. The folks at work had a lot of fun with them. One of my favs was the Wasabi version:
http://www.youtube.com/watch?v=mZk7-1uGmc4