Some gadgets are okay. But they are hard to (re)discover between thousands of crap gadgets. So it pisses you off when you discover the "Windows Easy Transfer" wizard didn't include them in it's backup when you are (re)installing Windows 7.

How to migrate your Windws 7 Gadgets

So to help you do it yourself, copy the following folder to your new installation of Windows 7:

%UserProfile%\AppData\Local\Microsoft\Windows Sidebar\

Ofcourse, if you've already installed Windows and you have your old installation sitting on a drive mounted as W:, you'll be looking for:

W:\Users\username\AppData\Local\Microsoft\Windows Sidebar\

You can skip Cache and you're gonna have to manually merge Settings.ini if you've already found some new gadgets you also wanna keep.

Copy, overwrite, log out, log in.. tadaah! :D

Note:
If you didn't have any gadgets in your new Windows yet, you need to right-click your desktop and click on Gadgets once to activate the 'sidebar' (because that's how your invisible gadget overlay is called).

I thought I'd post this little fact because I couldn't find this anywhere on google.