Probably penguin. Of all the villains listed, he's the only one who actually has a LEGITIMATE business, the nightclub. Much less chance of Batman randomly swinging in and dislocating my jaw.
Also, Penguin is fairly unlikely to randomly kill you (unless you mention is height and weight), plus you get a swanky tuxedo to wear all the time. Probably also better paid than most other henchmen.
But really, with no other choice, I guess I'd work for any of them... except Joker. Never Joker. NEVER. Do I NEED to explain the life expectancy of Joker henchmen? No, I didn't think so.