hdmi does both audio and video. You'd have to have a stereo receiver that has it though.
I use HDMI from my satelite receiver to my TV but the optical from satelite to surround sound receiver...so I think I've got about as few cables as possible that way. My best bet to cut it down is to do HDMI from DVD to TV...good excuse to get a HD-DVD player some day. I don't route any sound through the TV.