We've added park hopper on previous trips but will not for the next trip. It's not the added cost, but rather a desire to take a more measured and relaxed approach to touring the parks. After a few trips of open to close park hopping (we would always end the day at Epcot, our favorite), I've realized that this is a great option for adding variety to the day but it also adds a lot of exhaustion and stress, not to mention travel time.
With proper planning, you can really make a full day out of each of the WDW parks, and see things that you usually skip when under the park hopping mandate...there are lots of other things to do (DT Disney, exploring the resorts, etc) other than just shuttling between the major parks.
I'll put my commando touring skills up against anyone, but we'll skip park hopping next time to see if we can recapture a bit of the ease that is supposed to be part of any good vacation...