I just wanted to report that my laptop (MacBook) fit in the in-room safe at the Animal Kingdom Lodge. I know this is a big question for a lot of people in the trip planning stage. There was still room to spare too. This is not going to work if you have a very large laptop though, and I don't know about the other resorts... this was the first time I took a computer along to WDW so I never really paid much attention before, but I was not planning on the safe being big enough at all, I was pleasantly surprised (and relieved because I couldn't find my cable lock before the trip).

My 14" Dell Inspiron fits in the All-Star and Pop Century and Port Orleans French Quarter wall safes, so I would hope that the Deluxe resorts work as well. It is a Good Thing to be able to lock up one's laptop during the day!