I'm surprised nobody has brought up Fallout:Tactics. For all that was wrong with that game, I thought they did a great job at the RTwP thing, so much so that I was never able to go back to Fallout 1 & 2 afterwards, since the combat seemed so primitive in comparison. And I'd love it if we could set ranged character to overwatch mode in Project Eternity. My go-to tactic in both Baldur's Gate games was to have my ranger sneak off, attack a group of mobs, and pull them back to the rest of the party, who would then wipe the mobs out with spells and missile weapons. Sadly, that type of gameplay has been tricky in more recent RTwP games, since companion controls have been so wonky and the AI so bad.
Also, since this subject has come up several times in this thread, I find turn-based combat to be far, far more immersion-breaking than RTwP.