; You can have additional command lines here for a multi-line script
There are a boatload more things you can do with AutoHotkey, including setting key combos to expand to longer text. For instance, btw followed by a space or comma could be set to type out "by the way." More-complex tasks include creating an on-screen volume display or making the backspace key in Windows 7 Explorer act the way it did in XP. It is a pretty complete scripting language, including support for variables, loops, regular expressions and file access, and it sports a bunch of user interface commands -- everything from sending mouse clicks to creating menus and manipulating windows.
AutoHotkey isn't exactly like AppleScript on the Mac. As far as I can tell, AutoHotkey can't really script specific applications -- beyond using GUI menu commands -- the way AppleScript can send commands to properly enabled apps. And recording your own activity to save as a script isn't nearly as elegant or intuitive as AppleScript's built-in keystroke recorder.
However, it offers a reasonable amount of the scripting functionality I've come to enjoy on my MacBook at work. AutoHotkey even outshines AppleScript in several areas, such as determining the active window; how I wish AppleScript had a simple command for this! AutoHotkey is also ahead when it comes to using regular expressions; AppleScript requires an external addition for this and is still not as robust as most other scripting languages.
As with AppleScript, you can compile your AutoHotkey scripts into executable files. In fact, compiled AutoHotkey files can run on any Windows machine, even if AutoHotkey isn't installed, making this an attractive platform for sharing productivity snippets.
If you haven't yet taken AutoHotkey for a spin, it's definitely worth a download.
The other keyboard macro app I've come to rely on is specific to Mozilla's Thunderbird e-mail program: Nostalgy. This plug-in allows you to assign keys for copying messages from or moving them to various folders.