I've always liked to imagine him as a classy guy, but not Hannibal Lecter type, that would be scarecrow. I think he would be very funny and egocentric, a bit harmless looking, while in fact he's a manipulative, incredibly intelligent and sadistic bastard.
I like this one a lot. Certainly better than the tights/jumpsuit Riddler. I'm more partial towards a balance between the two, though. Mainly because he doesn't seem to be the type to miss a chance to brag in a loud manner. And I like the bowler hat.
I like this version of the Riddler; he's definitely more refined with no goofy tights or silly hat. The mood you gave him is good; darker and more thoughtful. He's more believable and thus more intriguing.