Peaches, I soooo forgot about Dune. Thanks for reminding me.
Now, to remind you of one more Dune game: Emperor, battle for Dune.
I loved the idea of the game, though it troubled me that the maps were way to small and the gameplay was annoying sometimes. But the combination of all things: using the smaller "factions" (Guild, Fremen etc.), the sandstorms and, above all, riding the sandworms, made a few nice things. Also, it is one of the first RTS games where you could look at the battlefield from a 360 degree perspective.