1) What type of digital connection do you prefer? TOSlink or S/PDIF?
I prefer S/PDIF because it can use the same cables as those used in other HT applications, and it is much easier to connect, especially if you are reaching around back from the front of your equipment.
2) What is the connection type you use with your system? TOSlink, S/PDIF or both?
TOSlink, because it seems every piece of hardware comes with that standard. Also, my receiver has more TOSlink
3) Which connection sounds the best? TOSlink or S/PDIF?
Have never heard a difference
4) What types of connection does your audio equipment have? TOSlink, S/PDIF or both?
Both, mostly