How to max setup for Squeezebox touch?

OK. Bought a Touch and setup with RCA jacks while my cd/dac was in the shop. Now got it back and want to run thru the Dac. What is better as far as the SPDif vs Optical? I dont have either so i need to buy a connection. Also, what other tweaks shoudl I be looking at that are no cost just part of teh setup.I upgraded my router to N and that was great, also updated the firmware. Runs well sounds decent and I am enjoying the Internet radio especially as we are a desert out here in HI for jazz, etc other than public radio. What else shoudl do to my PC or the sw to improve it. The new power supply will have to wait a bit but are there tweaks?