If you're bored with being greeted by the same blue Windows 7 login screen as everyone else, customising it is pretty easy. With a few free tools, you can have a login screen all your own.
These instructions are only for Windows 7! Please do not try this on earlier versions of Windows.
Changing the Background
If you don't love blue, or just like to have your own look, you probably love the idea of changing the Windows 7 login screen background to something else. Fortunately this is pretty easy to accomplish with Logon Editor, which is software for customising your login screen background, and a wallpaper image of your choosing. (If you need some wallpaper, be sure to check these out.) To get started, open up the app and you'll see an option up top that says "Background Image" along with a "Browse" button. Click the button, locate the image you want to use, and choose it. This will change your background. The app will also let you customise your username and change a few styles. While there are options for branding customisations, you can only change the branding to existing Windows branding images—but that's okay! We've got another app that'll let you change the branding image to whatever you want.
Changing the Branding
Once you've got a custom wallpaper in place, if you want to remove the Windows 7 Branding and use some of your own you can do that pretty easily. All you need is a little tool called Windows 7 Branding Changer and a branding image that's approximately 361x58 in size (to avoid stretching). To replace the branding, simply load up the app, click "Load Picture," select the picture you want to use for your branding, and then click "Apply". You're done!