Wow -- fun to have this thread revived.
Lots of things have changed since it was started. We now really have only one charter in the San Juan's, LuJac's Quest; Bandito sends their smaller boat up there occasionally, but not often, and the Naknek is gone. Porthole Charters is also gone, but the Aluminator boat does central Sound charters nowadays.
To my list of great Puget Sound dive sites, I've added Point Hudson up in Port Townsend, which is kind of like Keystone jetty, but I think even better for color and density of life (and Cockerel's dorids!). Flagpole, out in Hood Canal, is an outrageous dive, but parking's a little complicated and the schlep to the water is non-trivial. In addition, it's a long surface swim to the buoy, unless you have a scooter. Still, people do it, and the dive is great, as is Jorsted Creek, which is also an adventure in gear moving.