The Flaptop bag by Inside Line Equipment — who also make the Porteur Rackbag I wrote about not long ago — is a comfortable, durable, and waterproof messenger-style backpack. It's got one large main compartment that can keep your stuff dry and protected in any weather, with several smaller pockets inside and outside.

This 1000D Cordura bag is large enough that the two deep exterior front pockets can actually hold shoes if needed. Each of those compartments has small organizational pockets within for pens and a phone. There are also two side pockets, plus three small pockets inside the top of the main compartment.

The large top flap velcros down to stay in place, or you can use its built-in compression straps to carry a large object or even a bike wheel:

Get the Flaptop for $280–$300 at ILE, depending on your color choice.