iswitchb-mode is a cool little thing I recently discovered. I somehow enabled it accidentally, was puzzled for a moment until I realized what it was doing, and now I love it.
If you like iswitchb-mode, try out ido-mode (http://www.emacswiki.org/emacs/InteractivelyDoThings). It's like iswitchb-mode, but it also works with C-x C-f. I assume it does more than that, but I haven't looked specifically for the differences. I don't think you should have both of them, though.
