i just shot my first wedding about 3 weeks ago....
not something i thoroughly enjoy, i'm mostly into doing journalistic type photos.
my tips:
-have some fast glass. f/2.8 at the very least. they do get pricey though.
-extra batteries.
-double the amount of storage cards you are thinking about using, i thought i would be okay with two 4gb cf cards and i filled both up almost during a 6 hour period.
-KNOW your equipment. get some time using it in the settings you'll be shooting in. scout out the place so you know what to expect.
-backup body for sure. i used and old D50 i sold to my friends before. didn't have to actually use it for anything, but if my d300 crapped out on me, i didn't want to be useless.
i shot it using a D300, 17-70 f/3.5, 70-200 f/2.8, and 50 f/1.8 with a lowend sb600 flash.
for the ceremony i used the 70-200mm the most.
portraits and family pictures the 50mm
and the reception i used the 17-70mm
being this was my first wedding, it was kind of stressful.
the biggest problems i ran into was lighting for the group photos. with the on camera flash only i didn't get as good of shots as i wanted.
you can check out some of the pics on my flickr
http://www.flickr.com/photos/ocbaud/sets/72157606154165529/
that way you may be able to get some ideas.
oh, and the raw thing. don't give them the raw photos. they won't care and they won't need them. when me and my wife got married i had the guy give me the raw photos included with the jpegs(cost an extra $200) but since i do photography myself, it would give me the chance to edit the photos how i see fit.