In all my years of installing home theaters I’ve never heard someone say “man you ran too many cables”. One thing I do hear consistently is “man I wish I ran more cable before we finished this wall”. You can never run too many cables. Let me repeat, you can NEVER run too many cables.
At the cost per cable (what a couple bucks?) you should plan ahead and max out your capabilities. Run as many speaker wires as you may need. This may include running extra speaker wire to upgrade to a 7.1 from a 5.1 in the future or running extra wire to the edge of the room to poke into your bedroom for music. Either way its a good idea. Another cable to consider is ethernet (yes network cable, streaming high-def video is the wave of the future and you will want to be involved). Take this post to heart and over do your system every single time.