i also use a 50mm f/1.8D for my D40x. it's an all-around lens. great for portraits as well as landscape shots. it's a fast lens, considering its max aperture at f/1.8, so this is also good for night shots. it produces REALLY sharp pictures. in my case, since it's not AF-S, i'd have to manually focus it, but the metering works with no problem.
(bought mine sa hidalgo for 5k.)