Drop by drop (literally, the sort of amount you'd get from an eye dropper) is a good way of getting a cask strength whisky to just where you like it, and to see how it develops, but on the whole I go with Harry: I like them neat with a glass of water on the side, so you can dilute in the mouth.
P.S. This really only refers to scotch: I don't think bourbon really goes with water at all, unless it's something like one of the cask-strength Wild Turkeys or the Cadenheads cask-strength bottlings. And I've never drunk Irish any way other than straight.
[This message has been edited by Gate (edited 05 November 2002).]