Nathan is an Old Testament name that's been steadily on the upswing for forty years and is now at Number 31. Strong, solid, and attractive, Nathan was chosen for his son by Jon Stewart. It's a name familiar to every schoolchild through Nathan Hale, the Revolutionary War spy.
In the Old Testament, Nathan was the name of a prophet and also that of one of King David's sons. It is mega popular in Europe right now, the Number 1 name in France and Number Three in Belgium.
Nat and Nate (as featured on TV shows like Six Feet Under (and Gossip Girl) are just the kind of friendly, old-fashioned nicknames that are now very much in style.
Nathans have starred in some classic films--it was the name of the character played by Kevin Kline in Sophie's Choice, by Jack Nicholson in A Few Good Men, and Frank Sinatra was Nathan Detroit in the film version of Guys and Dolls. Nathan Zuckerman is the protagonist of several novels by Philip Roth.
In the public eye right now is Nathan Fillion, who portrays TV's Castle.