Windows: HotKeyP is a free utility that allows you to create custom keyboard shortcuts to launch any application, perform any Windows system command, open any document or folder, and more. If you're the type who prefers to work with as many keyboard commands as possible, the app is worth a look.
HotKeyP supports multimedia keys if you have them on your keyboard, and allows you to assign any key command you like (as long as it's not in use by Windows) to Windows system commands, launch applications or open specific folders, open specific documents, or load even load your favourite websites.
Plus, the app is portable, so you can toss it on a USB key or into your Dropbox account and run it from any system you use. Do you have a favourite app to add or manage keyboard shortcuts on your system? Let us know in the comments.