One of the biggest eye sore in a home office is commonly cable clutter. A nice solution for this is to attach a rain gutter towards the back of a desk. Check out this great before and after from SeanDavid010 over at LifeHacker:
Much better right? For more photos and to read about how he did it, click here. For another great example on how to use a rain gutter for cable management, also check out this post by Jonathan Crossman.