I read somewhere that button is supposed to size the window to fit all of its current contents. But I'm with you: for me, it's useless. This seems to be a fairly constant "recent switcher" complaint.
Uhhh, no. Not even close. Quicksilver shines when you are doing keyboard-intensive work (writing). it lets you do all sorts of things (including launching apps, but that's just scratching the surface) without taking your hands off the keyboard.
Dave - excellent writeup. It mirrors many of my own switching experiences. The launching issue has inspired all kinds of apps. I've heard good things about LaunchBar. I'm currently using Quicksilver, which does a lot of cool things besides launching apps (although I'm still new with it and...