Everything that Microprose ever did (in the simulation line) but especially Task Force 1942, Red Storm Rising & M1 Tank Platoon.
Interestingly the RSR remake currently underway
here may get a graphical overhaul once M.Franssen has recreated the original as was.
The 'holy grail of subsims' that was Dynamix "Aces of the Deep"
The classic 'Carrier Command' (that is actually happening!)
(although it isn't really that old) "Destroyer Command"
SSI's 'Fighting Steel' would be great with a graphical makeover (Jutland is a great replacement! in the meantime)
The early PC/Amiga turn based naval wargame "Dreadnought's" by Peter Turcan would be amazing with today's graphics.