It might not be even worth getting a Ghost type considering you need to trade to get both Gengar and Dusknoir. Froslass is a possiblity, but it requires either the Pokewalker or Migration, so it might not be what you are looking for. The next best option is Mismagius, which isn't that bad if you use it well, like my brother does (my brother uses a team of misfits: Meganium, Persian, Gallade, Mismagius, Aggron, and Vaporeon.)
