After work I went down to Running Fit and picked up some new shoes. While I was there I found a Garneau Revo transition bag that fits all my needs and some needs I didn't even know I had. For example, it came with a tripod style folding chair.
On the back it has a place for a bike helmet. The sides sport mesh pockets for drinks. And there's a nifty quick access compartment on the side for tools.
There are four main compartments. Three in the core of the bag and one, vented one, on the bottom. The first compartment is a pretty simple space.
The second compartment is the biggest and has the most pockets for organizing stuff.
Then it opens up to reveal a shoe compartment.
The bottom compartment has mesh vents on the bottom and will be great for keeping moist textiles from getting too raunchy.