Oh my! There are so many to choose from! I'll try to restrict to one for each ship type in each navy. Let's see...
Royal Navy - Illustrious(WW2), Ark Royal (yes, the one that had been "sunk" many times over.), Rodney, Repulse, Belfast, Dido, Tribal, O Class
Kriegsmarine - Prinz Eugen, Scharnhorst/Gneisenau. I've got a 1/400 Graf Spee by Trumpeter so I'm quite contented.
USN - Midway in her original configuration, Tarawa, South Dakota, Tennessee(late WW2), Yes, Any US battleship with cage mast will be a great idea, Atlanta, Alaska, Ward, Cassin, Any LSTs
IJN - Akigi(Time for an updated version of her), Kaga, Nagato, Ise(Hybrid version), Takao, Yahagi, Tone, Mutsuki (one of those early destroyers)
Soviet Navy - Admiral Kuzetsnov, Kiev, Kirov, One of those gigantic hovercraft.
Finally, I've develop a facination of late for the Pre-dreadnoughts & ironclads. I know maybe it's not be very commecially viable to produce many of them. Perhaps the more famous ones will be sellable like the Mikasa, Pomtemkhin/Retvizan, or one of those Czarist funnies like Adm Nakhimov, Oregon, Maine, a Bouvet or Hoche, TingYuen(of the Battle of Yellow Sea fame, ZhengDeFu had produce on in 1/300 scale almost 10 years ago, but it absolutely dismaying. Maybe Trumpeter can think of a new kit that will do some justice to her, at least tons of mainland Chinese will buy, if they are worried about the market.) Or perhaps they can produce them in 1/200 scale, they are small enough to not take up that much space even at this scale. I dun remember any one release any kits in this scale since Nichimo...oh my, I'm getting delirious... argggghhhhhh!.... Hello! Anybody out there hear us?? If you are in favour of this idea, write in to support, I'll be most grateful.