The only feature of the iPad 2 that would make me upgrade from iPad 1 is the reputably better web surfing experience.
I do find the it annoying when browser window has to reload when working with two or three open windows. Also the time it can sometimes take for images to load. It's not a big problem, and iPad 1 is still a marvelous device. But faster/more powerful would be better.
So how much better is iPad 2 ?