Well, recently for a prototype we've been working on, we had to create a flash-based pedigree. We thought that rather than just do a knock-off of every pedigree out there, we'd try to implement some of these features. We determined it would take about the same time either way so we went for it. We learned some really interesting things.
1) There is a cool factor about being able to navigate a pedigree like this.
2) It is meaningful on multiple levels to be able to see your whole pedigree.
3) This pedigree seems to provide better context.
4) Interesting information can be communicated at a glance. For example, when my pedigree is all of the way zoomed out it is easy to see that I have a couple of holes in my 6th generation. This may be a logical starting point for some research.
Here is a screenshot of my pedigree all of the way zoomed out.
(Click for a larger view)
If you count you can see 54 generations (a cousin of mine hooked up to a royalty line that I left in for testing purposes...). You can't really see in the screenshot but as you mouse over people their ancestors all light up in one color and their descendants all line up in another color. If you click on a person their details pop up. We're considering putting this up on a server where people can play with it. Anyone interested?