Take a look at the 9 speed SRAM I-Motion. It offers a wider gear range than Nexus, more uniform gear steps, better efficiency in the middle gears, and quicker wheel removal/installation with its quick release cable connector.



Given that you're looking at running a dynohub, I'd strongly encourage you to consider the Sturmey X-FDD dynhub/drum brake hub. It offers comparable braking to V-Brakes in the dry, but nothing comes close in the wet, and your brake pads and rims last MUCH longer.