Call a few (at least 1 ) more that do reasonable work (you would use them if they were wildly below the other guy). See what the going rate is for the job you want.
See where you can reasonably cut out something expensive. (Do you need 2 video/ or is it ok to 'miss' something, cv"s?)
Ask people what they considered important in the photographer. What type of pictures do you want/ need : artsy, many portraits , of the couple or everyone else (large family), lots of dancing...? Which pictures came out best in your friends' albums- the type important to you or not? Must he be a mentsh to work with (or you can work with a finagler)? Does he help with picking the album pictures or do you not need that? etc..
(It's nice to get a high quality CD with all the pictures after you've all chosen your albums. blow-ups of the nieces, uncles...)