Oh, you need to put Russell Johnson from Gilligan's Island in there somewhere. He wanted to do a Star Trek and never got a chance.
And my two wish-they-hads are Leslie Nielsen as some crazy Starfleet officer ala Garth or Ron Tracey, and Ed Asner as a Klingon.
Ed Asner would have been an awesome Klingon! And imagine an exchange between The Professor and Spock..
I consider Forbidden Planet to be the prototype for Trek (whether intentional or not), and JJ Adams is certainly the spiritual ancestor of Captain Kirk, so Leslie Nielsen would have been right at home in a TOS episode.