I've started using Keyboard Maestro recently and it is one impressive piece of software. Here are a couple of the macros I've written that aren't completely tied to my system:
Type current Safari URL - This will type the URL of the frontmost Safari tab/window into your current application. Handy if you're chatting with someone and want to paste them a hilarious YouTube URL without switching apps, copying the URL to the clipboard and switching back. - It does not use the clipboard, it actually types the URL into the current application, so any modifier keys you hold will change what is being typed. I've configured the macro to fire when the specified hotkey is released, to minimise the chances of this happening.
Toggle Caffeine - Very simple, just toggles the state of Caffeine with a hotkey.