Like many others I have just registered to contribute sth. to this topic.
I would really enjoy another old school RPG like Baldurs Gate.
Additionally, I would be very glad to see it in the Forgotten Realms scenario of the DnD universe. It goes without saying that this would mean a complex battle system based on the DnD rules and a deep story with nice characters etc.
From my point of view you could just use the old NWN2 engine or even 2D graphics to create a nice isometric game.