Can't speak highly enough for the Oyster card deal. Applied for it earlier this year and used it for a family break, saved bucket loads.
Just got back from a States trip where flashing the plastic was also very useful, fortunately not the plastic Mrs GF is used to...
As Noregrets previously stated, Sea World, Busch Gardens free entry. Universal will reduce fees on entry. Unfortunately no recognition with Disney, seemed to be a US military focus only.
Stepping aside from the financial aspects - it was actually quite humbling to see the approach to the military effort. The punchy Here's to heroes DVD prior to the Shamu Seaworld show and the subsequent applause for the military had gave my wife a real onion cutting moment.
It's good to see we are moving in the right direction.