Obvious dirty humor aside, one of the killer apps that I can't live without, is the mouse gesture app StrokeIt.
StrokeIt is a tiny program that runs in your system tray, that allows you to configure customised mouse gestures for windows, or any program on your computer.
I use StrokeIt to speed up the small repetitive things I do every day, and there's probably a lot more that I should use it for. Here are some of my micro-tasks that I've gesturized:
A gesture can run applications, excecute key combinations or hotkeys, type stuff, run scripts, pretty much anything. Download it and check it out. Its also free for personal use, or $10 for a business licence.