I have just a few things to add to this great thread....
I ran the full marathon last year--things that I recall as being important:
If you want something you see at the EXPO, buy it then! (We didn't want to jinx ourselves by puchasing the "I did it" T-shirt before the race and never found it again---many frustrating phone calls from home to Wide World of Sports)
If you need to pick up someone elses race packet at the EXPO you can, you just have to have: photo copy of their driver's license, thier Official Race Number Pick-up Card and signed Waiver. I also had a signed letter stating it was okay for me to pick it up. My husband got into Orlando late the afternoon before the race. The packet pick up and a quick walk thru of the expo took us a good hour. The parking lot was almost full when we got there. We did not really stop at any of the booths----it was wall-to-wall people w/ not enough space in there.
We stayed at BWI & we got to the bus about 330a. Yes, it is early but we survived and will do the same thing again this year. It is nearly impossible to walk from any of the EPCOT resorts to the start. They say the last bus runs at 4am, I don't know how true that is but I wasn't willing to risk it after all the training we had put in. Personally, if I were to stay on the monorail I would probably get on it by 430a. We will probably aim to be on the bus by 4am this year instead of 330am.
Lots of people at the port o potties outside AK w/ long waits.
Yellow Gatorade, lots of flavors of power gel and powerbars, bannanas, oranges (just one food station had oranges, I believe mile 13 or 14--they tasted SOOO good I wanted more to have them!!!), water sponges around mile 18, candy at 2 stations--one was mile 23 and one was somewhere around mile 9??) They also provide HUGE containers of an "icy hot" type product that people were slathering all over themselves. The volunteers will also rub it in if needed. Many medical tents sent up along the route.
The only place I saw COKE was at the finish line--I did not see any soda on the course, and I was desperate enough a few times to take one if I would have seen one
One thing about eating/drinking--don't don't don't do anything on race day that you haven't been doing in training. Getting sick while trying to finish a half or full marathon is NOT FUN!
I wore a fanny pack and it worked out great. I will carry a cell phone in my fanny pack this year--my family was not able to meet us at our "designated" spots d/t traffic issues and getting stuck on a disney bus for an hour (
they drove to TTC and that was a huge mistake. Anyone trying to get around to cheer on race mornings should use the monorail. 
) Maybe w/ the races split on 2 days the traffic won't be such an issue but I personally wouldn't risk it.
Things that i personally will have in my fanny pack: cell phone, I-Pod, power gu of my flavor (vanilla--I don't want to risk them not having it), kleenex, chap stick, aqua-phor (I use this in the "rub" spots), park hopper (we walk thru EPCOT after the race back to BWI), room key. I would also make sure you get a fanny pack that is intended for running and try it out before the marathon. Another great idea is to try out your clothes before race morning--make sure they are comfortable!
We had massages at the BW the afternoon after the race. It was good and I believe it helped the next day but the therapists are a bit hesitant to get deep they day of the race

. I do know that they did not have any appointments so if you plan on having a massage the day of or the day after the race make arrangements NOW!!!
Happy training....the accomplishment of all the physical training and mental anguish leading up to that morning will overwhelm you with emotions!