I wouldn’t be so quick to discount Dreadnought. The ship’s battle record may not match that of the World War II battleships, but her design was so revolutionary that her name was the descriptor for every battleship to come after her. So much so that battleships are generally divided as either pre-dreadnoughts or dreadnoughts.
Although the Iowa class is, without a doubt, the epitome of battleship design (if in doubt read the fine analysis linked by sailboat), I don’t think they ever fired a round at another ship of their class to prove it. That honor goes to the South Dakota and * Washington* during the Guadalcanal campaign and to Adm Oldendorf’s six old battleships (five of them raised from the wreckage at Pearl Harbor) in Surigao Straight.
My personal favorite is the Texas. The oldest dreadnought that survives and my introduction to the battleship.