You can get mx products for securing the cables behind the setup. Make sure you dont tie the power supply cables with interconnects and speaker cables. also try not to create loops in interconnects and speaker cables. I read somewhere it might effect sound quality, no personal experience though in this regard.
For the surround speakers' wires, you can get the external casing done. You get modi brand casing for about 30-35 bucks for a 6 (or is it 8) feet length. You better get an electrician for this as he'll probably do a much cleaner job.