In addition to the comments above, I also row from my drybox and store emergency items such as the first aid kit, repair kit, a headlamp, etc. Basically, anything I would want to access to immediately. I went a step further and made some dividers to help keep things organized. They are made out of 1/4 material and can be moved in one inch increments to accommodate whatever is in there for a given trip. I can't say enough about how much this has helped my sanity.
Before, when it was just a black hole, there would always be someone digging in there and not re-organizing so that I could never grab what I wanted when I wanted it without digging around. The divider system is basically some 3/4 x 4 material with slots in it. No need to glue it in or otherwise attach it permanently because the dividers and contents of the box keep everything snug.
I built the divider system in about an hour for both my drybox and kitchen box and it was less than $30 in materials. It was one of the best things I have ever done in regards to rigging, right up there with the everything bag.
Disclaimer: We are a family of 4 and boat with our dogs more often than not so my wife handles the kids and critters while I am in charge of rigging and organizing camp so I am always looking for ways to maximize space and free up more time for myself. I couldn't imagine going without my drybox anymore