I agree that Dry Suit is the way to go as far as indisputable warmth, but regardless I use a farmer john 3mm wet suit, chaco's, and a rain coat or splash top, depending on weather/run.
My sister who has poor circulation (Raynauds) is always cold. She's super warm and cozy in a 6mm long sleeve wet suit, neoprene booties, and a splash top. She'll usually wear neoprene gloves as well if we're going to get very wet. (Westwater)
I like the versatility of the farmer john's, easy to add more, but light enough to shed layers on warmer days in cold water. My two cents FWIW.