Mac only: Having a 2TB drive filled with movies and games is beautiful, but OS X's default .iso icons sure aren't. Free app SlipCover solves this problem by quickly creating custom case icons to jazz up your media collection.
SlipCover is a simple drag-and-drop ordeal. Just drag any number of picture files (say, movie posters) into SlipCover's window and it will automatically make .icns files for each of those images, branded as DVD, Blu-Ray or HD DVD. You can then drag these images to the finder to save them as .icns files, or, even easier, drag your media files onto their respective cases to apply the icons directly. It's simple, but very customisable — you can download other case types (such as Xbox 360 or Nintendo Wii) from the net or even make your own, using the instructions on SlipCover's website.
SlipCover is a free download, Mac OS X only.