One of the most handsome names known to man, in my opinion! Marvin sounds amazing, has that classy feel, isn't overused, is fun to write, and even has cool nicknames (Marv, Vinny, Marvelous)! Marvin Zachary is my top combination, at the moment.
I don't think Marvin sounds too nerdy, I like it quite a bit and think it's more charming than Martin. I think the v makes it more pleasant to say. But maybe I'm biased since Marvin the Martian is my favorite Looney Tunes character, lol.
Although I am a Marvin Gaye fan, I am anything but a fan of the name Marvin and I don't think it's cool. It sounds a bit like the name Mervyn which is definitely uncool and nerdy.