This is the back of my Palermo office desk (you can find more details about my office setup HERE).
All peripherals, a power strip, and power bricks are mounted to a piece of pegboard that is attached to the back of the desk via two "L" brackets (also known as shelf or corner brackets). The cables are attached to the back of the desk and leg via adhesive backed nylon mounting bases (available at The Home Depot & Fry's Electronics).
The photo is for my Declutter The Mess Under Your Desk! blog post.