The interesting thing I've noticed is that my typing speed seems to increase dramatically right after I've finished with a session of hard-core piano practice -- especially if I've been practicing a quick-tempo song, like Mozart's Rondo Alla Turca. I also think my typing is more accurate after a piano-playing session. Any other monks notice this effect? (I'm definitely gonna keep a link to that Java applet for the next time I really get going on the piano... time for some empirical study.)

Another think: I'm a self-taught typist, just as I am a self-taught pianist; can't play music from a piano book (well), just as I can't type stuff straight out of a book (well) either. All I know is that formally-taught keyboardists (whether computer or musical) often wonder how I can do what I do with such lousy style. ;p