Originally Posted by
Adekis
They're both "real", but I think that's sort of a cop-out answer to avoid the question. Fundamentally, I always prefer to think of Superman as "Kal" if he's not "in-character" as Clark Kent, or talking to his parents. There are exceptions: Byrne's Superman was so Clark Kent that I often call him that regardless of what he's wearing- but generally, it's Kal all the way.
The way I see it, Kal asked himself two questions: What would I do if I was the strongest man in the world, and what would I do if I wasn't? The secret identity allows him to have it both ways, but he fundamentally has the same answer to both questions: help people with whatever means are at his disposal. For Clark that means his writing ability and his mundane detective skills, occasionally aided by enhanced hearing or see-through vision of course, and for Superman that means leaping in the way of bullets, catching out-of-control trains before they can crash, and getting corrupt businessmen and politicians out of powers through potentially less-than-legal means.
I've never liked the idea of the "Smallville Clark" / "Metropolis Clark" distinction, because I've never liked the idea that Clark Kent, mild mannered reporter, isn't fundamentally who Kal-El is. He backs down more than Superman does, but Superman never has to back down; Clark is like everyone else. "Metropolis Clark" is "Smallville Clark", or as I like to think of him, "Kal". He's just got his guard up a bit more, and has a few more affected traits, like slouching, wearing clothes too big for him, pitching his voice as a tenor instead of a baritone, etc. I feel much more strongly about Superman being a disguise though- I think Superman, like Clark, is Kal "on guard"- but significantly less so than Clark is. I always liked the idea that Superman would be very relaxed.
I basically cut "Superman" out of my conception of how the secret identity works- our hero has two names, probably thinks of himself as both "Clark" and "Kal", gets called "Superman" and answers to it (and, I suppose, likes it), but when he had to say his name backward fighting Vyndktvx, he said "lE-laK! tneK kralC!", which indicates to me (and I like the idea) that of Kal's three "selves", "Superman" is the one that's just a nickname, and there isn't really a third identity. Just Kal and Kal "on guard" and in-character as Clark.