How many camera batteries do you need for a wedding?

Nikon D3000 camera batteries. If you have 3 fully charged batteries will they last from 8am-10pm the same day?

Also if you have four 2GB sd cards, two 8GB sd cards and one 4GB memory card… Will those be enough to shoot in raw format the whole time?

I have extra batteries for everything, but one camera battery will last the entire wedding day on both my D80 and D300. That is not using the on-board flash at all.

I also shoot only the formals and the ceremony in RAW, so yes, that much memory would do me just fine. Also I do not shoot thousands of images, a normal 8 hour wedding day I will shoot around 400- 500 usually and deliver 250-300 of those. If you shoot two thousand RAW+jpeg, you may need more memory.

A battery grip with two batteries lasts for entire weddings with my Canon 5D Mk II and T2i.
But you should have at least two extra batteries for each camera anyway.

How many memory cards you need will depend on the length of the wedding and how you shoot… But I would suggest a couple more 8GB cards.

Wedding photography is HARD. If you're getting paid to do this, you should be getting paid good money for it.

You should buy and carry enough fully charged batteries to last you longer than you think you need. Same with flash cards. Why would you even want to carry two 2 gig and one 4gig card when another 4 gig, or even better, an 8 gig card will help assure you don't miss a shot, or keep your clients waiting while you switch out a full card? Sure, keep the others carry them for spares. But the point is that asking us if we THINK you have enough, won't help you if you end up short at a critical time.

Things that effect battery life: do you walk around with the camera powered on all the time, or do you depend on the auto shut off feature to save battery life? Do you use a lot of the camera's built in flash? Do you compose through the viewfinder or do you use the "live view" LED screen? Do you carry your spare batteries in a pocket next to your body, or in a camera bag or pouch on your belt? How long is the event, including the reception? We don't know these and other factors about you or the event to confidently answer your questions. My best GUESSTIMATE as that you PROBABLY have plenty of that gear. But are you going to trust my "probably" answer?

Go buy some more spares. A pro invests in his or her business.