The Van den Hul Optocoupler should be on your list. I also had a good experience with the cable that Kijanki recommends above. For $30, you can't go wrong.
Optical /Toslink
I'm connecting my Apple Tv to my Cambridge DacMagic and I want to use a good grade optical/toslink cable. The grade of cable that I currently use elsewhere in my system is Kimber Hero, 8TC and D60. I know very little about optical and I'd appreciiate your recommendations to shortcut the learning curve.