^ He sang it again recently
Nimoy is awesome
About getting past Trek in terms of acting ability:
Anyways Nimoy did do other things besides Spock, it is just that Spock is such an iconic character of course he is going to be most associated with that. A lot of actors don't handle this well, I think Nimoy has and I have a lot of respect for him for that. Yeah I know there were the "I am Not Spock" days but I think that was taken out of proportion and he has certainly embraced his role as Spock now.
I like Shatner too (great sense of humor) but he is famous for being Shatner more so than being a great actor. I know he won an Emmy but I would still say his best known role of the general public is Captain Kirk.
De Kelley was in a lot of stuff before Trek. Never a leading actor but a good character actor, underrated in my opinion. I don't think he was given the chances he deserved and after Trek he was even a bit lazy by his own admission.