Windows Explorer – Diff two files from the context menu

Then Autohotkey is your new best friend. You program whatever hot key you like to do/launch whatever command or program you require. For example '#z::Run www.autohotkey.com' means when you press the windows key and Z together, it will run autohotkey's website. Or

^!n::
IfWinExist Untitled - Notepad
    WinActivate
else
    Run Notepad
return

means when you press CTRL+ALT+N it checks to see if you already have an unsaved/new notepad window open and brings it to the foreground. If you do not have one already open the key presses will open a new notepad window for you.

It has a very shallow learning curve with alot of good tutorials and examples to follow.

N I don't work for them :) but I do love the product, and I hope it helps you as much as it did me!

You can use power toys 'Open Command Window Here' for Windows XP to open a command window pointing directly at the selected folder.

EDIT

I'm not a Windows 7 user (yet) but apparently if you press the 'Shift' key and right-click on any folder, you get some extra options like "Open Command Window Here".

See here for more info on this, it demonstrates how to enable this feature without pressing shift using some registry tweaks.