Myself and the gf are going there in July (29th to be exact, for 2 weeks), and we've decided to splash out extra and stay in the park itself, in the Dolphin hotel. I've stayed in Disney before in the Swan (sister hotel to the Dolphin), and you do get bonuses by being there, like easy transportation to all Disney parks, plus you're likely to be within walking distance of at least one park (the Dolphin is walking distance from Epcot, as well as the Boardwalk, and Fantasia Gardens Miniature Golf Course).
As others have said, parks such as Universal, Universal Islands of Adventure and Seaworld are an absolute must. We'll be doing the Discovery Cove to swim with dolphins, and we'll likely be seeing the Cirque du Soleil at Downtown Disney.
Two weeks to see everything will be pushing it, but with good planning and a determination not to go back to the hotel when it gets too warm it should be easily possible. All Disney parks have water fountains all over the place so you'll always be able to get a cool drink of water when you get too hot.