ACTUALLY, now that I've heaped all this praise on FC, Valloric, could I just ask for one, teeny, weeny improvement???
I think that when a book validates, giant red rockets should shoot across my computer screen in triumphant arcs, and I'd really like it if the late Jeremy Brett's recorded voice (I'll take Robert Downey Jr. as Holmes if pushed) were to say something like "Egad, Hitch, you've DONE IT!!."
That's all. That's not too much to ask, is it? Lacking audio features, I'd settle for the Rockets. ;-)