The lenses are more important than the camera. Having said that my lens kit for wedding including FA 31, 43, DA*16-50mm and DA*50-135. Several things you will need to plan/know.
-learn about your role, can you shoot relatively close to the action, or are you only allowed to shoot from the perimeter?
-what are they looking for from your shots; mostly the bride/groom, their close families or guests?
-learn to know the environment; church (no flash), outside in the courtyard, evening dinner reception and the dance?
-learn how to use flash effectively (must for dinner reception and dance party)
-get to know the program well; anticipation - where do you position yourself for good shots?
Most important of all, have fun.... do not get uptight about not getting a shot (you don't want to miss the next one and the next one as well). Have some confidence and think positive that your shots will look better than the other guys.
Good luck on your assignment...
Oh, take RAW if you can... more headroom for errors