DH and I have done a few tours over the years. We've done the Backstage Magic, Magic Behind the Steam Trains, and Keys to the Kingdom. They all were great. If you want to capture the Magic of Disney, then I would suggest doing either Keys to the Kingdom or the Backstage Magic.
Backstage Magic takes all day and, in some ways, can show you too much of the magic. You will do some walking, but the tour group also have a private mini-bus and driver that drove us around the backstage areas and from park to park. On the bus, there was a cooler stocked with water bottles for our use. It's been about 5 years since we've taken the tour, so it may have changed. We saw backstage areas at Epcot and the inner workings of the American Adventure, Body Wars, and some tidbits for the Living Seas. In MGM we had lunch and saw many backstage areas, the customing area and prop department. Backstage at Fantasmic and Catastrophe Canyon. At the MK, we were taken to the area where the parade floats are stored. From there, we were taken through the utilidoor (sp?) where we saw many interesting things and up to the computer room where we saw how they monitor the parade and saw the parade start via the monitors in the computer room. From there, we were taken right to Main Street just as the parade was entering.
Keys to the Kingdom covers most of the MK stuff that the Backstage Stage tour does, but you also learn tidbits about Main Street and other areas of the park. We did get to ride Haunted Mansion after hearing about different things to look for and the Jungle Cruise without the normal dialogue. Lunch was at the Liberty tree Tavern. It's been 4 years since we've done this tour, so, it may have changed a little as well.
I'm willing to bet any tour you take will be fine. Read the discriptions and see what interests you.