This is something so simple that we wish we'd have thought of it. Instead of strewing your router, switch, cable modem, external hard disk, and other miscellaneous gear around your desk, grab a stack of letter trays and place them inside. They're compact, cheap, and have holes on the back and sides for cables to run. The trays are $2 each at OfficeMax so you can make a stack as high as your dad's old playboys.
The $8 Home Network Rack [Flickr - Thanks Rick!]