While Windows Phone 7 doesn't have nearly the customization features Windows Mobile has, you can make your Windows Phone your own by using custom wallpapers on the lock screen.
Windows Phone 7 comes preloaded with about eighteen photos that can be used as your wallpaper plus a hand full of solid colors. You also have the option of using one of your images as the wallpaper. You can find your wallpaper options in the Settings Menu under "Lock & Wallpaper" or you can set a picture in your Galleries under the options menu for the individual image.
WPCentral.com member Melk has started a discussion over in the forums asking everyone to share their wallpapers. As Melk mentions, a discussion we haven't seen much of. We've pulled a few from the discussion above and share Melk's curiosity.
So, head on over to this discussion and share your wallpaper or comment on what others are using.