Walter
From the Old German for 'powerful warrior'.
Alternatives: Walt, Wally (English slang for idiot), Walther, Watson, Watkins, Gautier, Gauthier, Ualtar.
Namesakes: Sir Walter Raleigh, Sir Walter Scott, Walter Cronkite, Walter Reed, Walter 'Red' Smith, Walter Winchell, Walt Disney, Barbara Walters.