Frank Sinatra is a bit overrated. Personally, I think Sammy Davis, Jr. was the most talented member of the Rat Pack.
Sinatra, Frank, Dean Martin, and Sammy Davis. The Rat Pack Live at the Sands. Hollywood, Calif: Capitol
He had it all--he could dance, sing, act, tell jokes, etc. He was a sharp dresser, too.
Was he a cool cat, or what?