Well, I'm looking forward to :
* pics of attraction signs - I do lots of layouts of inside rides and such and I've had to go on the Internet and "lift" a picture of the sign more than once lately, so I'm going to take a pic of every attraction sign I go to, just so I have 'em. Will only take a few seconds each time, and I'm sure I can go back and use many of them for years to come.
* lots of little details that many people may not notice. If you are leaving Wednesday, do you have a decent sized bookstore near you? You should try to pick up the Imagineers Field Guide to the MK, and/or the Imagineers Field Guide to Epcot. They are AMAZING, and best of all, CHEAP! Ten bucks each, and they are actually written by imagineers. They are EXCELLENT at pointing out the little details in the parks you may not notice or pick up on. For instance, Future World in Epcot. If you look closely, all the fountains, walkways, etc. on FW East (The Land, Imagination, Living Seas) are very curved and organic, while the same items at FW West are starker, harder lines, and points, etc. because that's the more "scientific/technical" side (M:S, Ellen, etc.). That's just one little detail - but I bet you could make a neat scrap layout of some close up shots. I highly recommend these books! Best Disney investment ever.
*hidden mickeys - you can print a list off from several places on the web, and try to photograph when you find them. Some neat ones are hidden pretty well, and it's so much fun to find them. You feel like you are "in" on a secret! I sense a layout, LOL. It's also fun to talk to CM's about them - they really like sharing that kind of info to interested folks.
*Come up with a theme or two and ahead of time and bring a list of pics to "look for" on your trip. For example, I'm doing an "A-Z of Disney" layout on my next trip - I'm going to find one or two examples of things that fit/have in them each letter of the alphabet. I don't have specific stuff in mind yet, really, so who knows where it will lead. I'm just going to bring a sheet of scrap paper in my pocket with a list of the letters in the alphabet and strike them off as I get an appropriate pic. Another idea I've always wanted to do is find a pic representative of, say, each month of the year (A picture of a heart-shaped pillow from Minnie's House for February, etc.).
*Vary the angle/orientation of your photos. This is one I always forget. I'm so concerned about keeping still (I'm terribly shaky, unfortunately, which I why I abandoned professional photography) that I forget to take portrait shots by turning the camera sideways, etc. Don't be afraid to take them from silly angles, upside down, etc., LOL. This is where the benefit of digital really shines - so what if you mess it up. You aren't wasting anything but a few seconds of time, and it's almost always worth it.
*Be on the lookout for fun photo opportunities - the backside of the Castle if you always do the front, a pic of your family in front of one of the talking trash cans, or take a pic of every waterfountain you see, LOL.
There is so much to look at at WDW, you can always find something new! Best advice, though, is to get those Imagineering Field guides - they will really help you appriciate all that you may pass by when you are running to Everest or Splash Mountain.
Hope this helps!
NED