platinum plugs dont work that great w/ our cars. The best ones to use are the autolight or motcraft plugs. There cheap and they work the best for our motors.
Since several people have given part numbers, I feel like I should mention something -- make sure you get the correct type of spark plug for your application. Autolite 24's and Autolite 3924's are equivalent plugs, with a different physical design -- the 24 is a beveled seat design to be used with iron heads. 3924's are a gasketed long-reach plug for use with aluminum heads. Do not use 24's with aluminum heads, you'll damage the head. And in case you were not aware, Autolite == Motorcraft.