Almost forgot - finding a stud is ALWAYS better, of course. I use 1 5/8" Deck Mate brand deck screws for all kinds of things - I like the way the coating makes them easier to drive, and I like the square-drive design (with included bit!). That way, you get ~1" into the stud after going through the drywall. Drywall screws work pretty good for things like this too. I'd be scared of using nails into just drywall, unless you took great care to drive them in at an appropriate angle.

bibere usque ad hilaritatem