A few of mine in order of favorites:
1. The Burger King. Seriously, whoever came up with this is genius.
2. The Quizno's spongmonkeys
3. The cat herding commercial. Although they sort of lose, since I don't remember the company, only the cats.
4. Geico commercials, but the Tiny House one wins above all.
5. Budweiser frogs (Bud. Wei. Ser.)