I'm a great fan of being able to navigate via keyboard short cuts, but in this day and age most people have more than you can access with a few quick keystrokes.

On my PowerBook in the days before Spotlight I used to rely on QuickSilver to let me find documents or start apps with a couple of keystrokes.

Then I found Baydens SlickRun for Windows and was hooked! It allows you to define sequences of characters to lauch an application or open a document - for instance hit your selected hotkey (I use Win+Space) and type IE to launch Internet Explorer, or FF for Firefox, or pwd to open a word document with commonly used passwords.

Launchy!

SlickRun isn't the only Windows app to do this. Launchy indexs the applications and documents it finds on your machine and performs a similar function. As you type it finds and matches applications or documents with those letters in the name (ranked in order of likely use)

A third solution is HotKeys. This takes the existing functionality of the Windows key and extends it - adding a pop-up on-screen keyboard to remind you what the short-cuts are, and giving you the ability to map new key combinations to just about anything you wan

Launchy looks a lot better than SlickRun (though the promised v4 of the latter does include a prettier UI) but doesn't seem to be quite as flexible or controllable. HotKeys has some built-in tools that are quite cool, but I'm not 100% sold on the large on-screen popup (though I do feel the Windows key is very under utilised). All of these seem to be fairly active in development so it's going to be interesting to see how they evolve over time. For the moment the minimalistic SlickRun is my tool of choice though.