BumpTop (available in Free and $29 Pro versions) takes your flat, two-dimensional Windows desktop and converts it into a 3D "room." It can help you organize your desktop files and icons, but its fun and good-looking approach consumes a fair bit of system resources.
You can spread your shortcuts and files out along the floor or four walls of BumpTop's room, or have a little fun by grabbing one and flinging it so that it 'bumps' against another surface. The app can help organize your stuff by gathering it into piles that you create yourself by drawing a circle around multiple icons and files, or you can have BumpTop automatically gather everything into 3-D stacks called piles based on their type (documents, folders, program shortcuts, etc.).
Once you create a pile, you can double-click on it to expand everything in the pile into a grid, and then collapse it back down. Right-click a pile for other options, such as fanning out the contained items or breaking up the pile.
BumpTop will start you out with a few picture frames. The frames can cycle through images pulled from a folder on your hard drive, or from an RSS feed from sites such as Flickr or Picasa Web. You'll also get a few widgets that can upload a picture to your Facebook account when you toss it onto the widget's icon, or start an e-mail with a flung file as an attachment.
You can also grow or shrink a given icon to make it more or less obvious, search for a particular keyword among your desktop items, or sift through a slideshow of pictures in the room. Program windows will display normally, and if you stop BumpTop by right-clicking its icon in the system tray, you'll see your regular Windows desktop.
BumpTop is fun to use, and its piles could help organize an unruly desktop. But it uses a fair bit of memory--about 110MB on my medium-powered test laptop--to maintain its 3D display, and will also use a good amount of your CPU when you move items around.
BumpTop comes in Free and Pro versions. The $29 Pro version adds additional features, such as flipping through items in a pile using your mouse wheel, or automatically growing the icons for files that you use often. You'll be prompted to choose Free or Pro when you install the app.