Well, first, I'd say it's important to distinguish "smarts" and "intelligence".
It's always been my understanding that intelligence is retained knowledge while smarts is applied knowledge. So if you're intelligent, that means you're very learned; if you're smart, that means you can think on your feet.
Keeping this in mind, the smart characters are probably going to be the most charismatic since intelligent characters are, oft times, portrayed as talkers who drone on and on about theory (thus far, the only writer who's been able to pull that off particularly well is Mamoru Ooshi). Rorschach and Nite Owl come to mind with the former being smart and the latter being intelligent.
As such, that would make Constantine smart.
I'd say a character like Batman is a synthesis of the two. Unfortunately, not many writers know how to handle that kind of character. Most seem more comfortable with doing one or the other or else them lose touch with the character.
An especially good example of a smart character is Berserk's Guts. He doesn't really plan for things, but he knows how to use the tools in his arsenal at a moment's notice and as efficiently as possible. And what seems to make Kentarou Miura's depiction of the character so effective is how well he's able to rationalize a scenario in which Guts survives a fight against all odds, but doesn't seem like a ridiculous Marty Stu in the process.
