My absolute favorite video advertisement is Carmen's J'Adore ad. Like Dale, that ad was really influential for me...I was really obsessed at that time with Dior HC FW 04 and Carmen Kass's J'Adore ads. It was those two things that introduced me to fashion and made me love it.
Here are some other notable video ads-
Dior Midnight Poison
Dior Addict High Shine (Love the music in this one)
Gucci Fall/ Winter 2007 Collection (this is really beautiful)
Gucci Fine Jewelry ft. Drew Barrymore (Drew looks really beautiful here)
Gwen Stefani "LAMB" perfume (I LOVE this commercial, especially when she comes out of the box at the end!)
Jean Paul Gaultier Perfume (Classique/ Le Male) (I adore these two SO much!)