Of that set, Lucerne would be my pick. It's a shared platform with the DTS, but without all the Cadillac frills, and with a V6 (N* was available in some of the top trim Lucerne's). I've never driven one, but I imagine it would be a nice cruiser, and with the 3.9L and the old 4-speed should be really reliable.
Those prices are horrendous though....