We really like FolkArt
metallic paint. You can find these very inexpensively at Michaels or Joanne's.
Benjamin Moore offers a few very nice metallic paints.
Some stores sell Modern Masters Metallic paints. These work great and
come in a variety of really nice very opaque colors. They are however much more expensive than the FolkArt metallics.
Nova is another
great brand if you are doing a larger project and want good quality metallics
in larger quantities. They are available online at http://www.novacolorpaint.com/.