Other good choices are Ludwigia sedoides (mosaic plant), Limnobium laevigatum (Frogbit), and Salvinia auriculata (a type of floating fern, and a personal fav).
Also, many stemmed plants do great floating (mostly ones with thin stems). There are a variety of carnivorous plants in the bladderwort family that are cool as floaters.
Floating plants are a great way to get the benefits of a planted tank without having to worry much about lighting, CO2, or fertilizors. Many types of fish such as Bettas, and Gouramis really are only happy when they have some floaters to hang out under.