In many cases, the best camera to use to supplement your network documentation is a small "sure shot" or cell phone camera. This is handy because it's easy to take with you. And since these little beauties now have 10+ megapixels.
I give some examples of how I've used my small cameras to document memory labels, equipment layouts, and more.
Remember: If you do this, there are security concerns. Don't use your camera as a "scanner" for documents and end up with secure information on an insecure medium!