The hottest new feature - not even discussed much on the Internet photo sites yet - is the "Highlight tone priority" feature. What's that you say - only the best thing since "P for Professional" for us JPEG wedding shooters. Here is the scoop - under C.FnII:3 of your custom functions - set to "Enable" Highlight tone priority.
You have now extended the dynamic range of your JPEGS - read this as meaning less chance of "blowing out the whites." Check out the before and after images here. The left image is about a stop overexposed, but by enabling Highlight tone priority, the resulting image on the right was saved!