Just got back from a week at Aulani last Friday, it's amazing.
- sunset from the infinity pool... last week, the sun set at 6:15 exactly... when it sets, it goes fast, so don't miss it at least one day, it's beyond words
- if you're driving to waikiki, park at the royal hawaiian shopping center and buy something (just about anything) to get your parking validated... it's reasonable price, and very convenient (parking elsewhere is not fun)
- do a morning whale watching cruise early during your trip when your body is still on mainland time
- The Menehune trail is really fun
- If you have any train fans, the Oahu railway is pretty close, but it ONLY runs on Sunday
- The Olelo room is a good option for a quick breakfast, and they do have poorly advertised hot breakfast sandwiches
- don't get your hopes up too high for 'ama 'ama... it's good, but not as good as you'd hope/expect

... it was our only real disappointment on the trip
I could go on and on, we're WDW and DLR regulars and go to Mayan Rivera regularly, and this was one of our best trips ever.
Please don't hesitate to ask!
Here's a cool tip I haven't seen anywhere else
if you walk on the path that runs between the beach and teh hotels and head west (to the right if you're facing the ocean) as far as it goes (past the sheraton), then go through the bushes around the point where it ends (there's a non-paved pathway there), there is a BEAUTIFUL natural cove with waves splashing up onto the beach. It's beautiful as it is, and when we were there a big Hawaiian Monk Seal was sleeping on the beach. It was an unexpected highlight of the trip for our animal loving 4 year old. It's not more than a 5 minute walk, and the path isn't the least bit difficult as long as you're not barefoot.