The classic Eric Cantona/Nike 'Good vs Evil' one:
http://www.youtube.com/watch?v=_MBOmL2x9IA
And a curent one thatI really like, featuring cider bottles that for some reason or other appear to live the life of Alaskan salmon:
http://www.youtube.com/watch?v=7qqhs5cLLd0
I also love a very old Tennant's Lager one with Escher's never-ending staircase, one from about ten years ago for Continentale tyres with a car stunt driver ('they think my stunts are crazy'), and an Ericcson mobile phones that involves children throwing snowballs at trams.