The RCA type audio cables do sound ok but it would be nice to have better cables if you own a high end sound system. It's too bad the wii dosn't support Dolby Digital 5.1 even though the games advertise they do.
It will do Dolby Pro Logic II. I have not seen a Wii game that says it supports Dolby Digital. Since the hardware doesn't support it, it would be impossible for the game to include it. Which game ads did you see?