I loved this advert, it's probably not my favorite of all time, but it was pretty amusing, and I have a terrible head for remembering adverts. 

My actual favourite is probably the Prada one, but that's for entirely silly reasons of liking the whole style of it, instead of it making me laugh.  I think it's really well shot and directed, and the concept works well too.

Or the Louis Vuitton one because I like the design, they had this on a big screen projection at an exhibition at the Baltic, and it's great...