I really loved Soul Calibur 2's opening. It had an awesome factor.
Metal Gear Solid, the original, had a nice opening in my opinion (as in, the intro cinematic before the main menu pops up) and sets the scene of the game really well.
BUT my faviourate opening cinematic of all time is Legend of Zelda: Wind Waker. The tapestry montage, and then the building up of the music until.... Violins (or whatever the fuck they are) play the Legend of Zelda theme tune and our spirits are lifted as it shows us the Hero of Time being just that - a hero.
Almost brought a tear to my eye first time I watched it. Really, really good opening.