How Human Should a Protagonist Be?

The protagonist is the good guy--someone everyone will root for. When he encounters the antagonist, everyone cheers for him to overcome the forces of evil. My question is, Does the protagonist always have to be good?

In Turbulence, I changed things around a little. My antagonist, Brad, is basically a good guy. But he has several unsavory habits which sometimes get the best of him. There are times when the reader can't stand him. In the end, though, he comes through.

I chose to make Brad very, very human--exposing all his ugly little habits, passions, and secrets. Some readers are uncomfortable with this. But I have always been attracted to the flawed character. Not the shining hero in white armor. Someone with dents in his armor and dirt under his nails.

In the long run, Brad is a good guy. He does the right thing, or at least tries. But Brad has some serious problems--ghosts left by his dead antagonist which continue to haunt.

I grew up in the days when the good guys were easily identifiable. The Lone Ranger was pleasant, in its day. I think, though, that we're ready for something more complex.