My favorite has always been The Fifth Element ever since I saw it.
I've always been a fan of futuristic movies and Bruce Willis. It has that combined. Add Milla Jovovich for eye candy, Chris Tucker as comedic relief, Ian Holm from the Jack the Ripper movie and Gary Oldman as the antagonist and I'm sold.
My wife loves it for the love story and the action/comedy is hands-down an instant classic.
"And now... Champagne!"