I've got a pair of Sharkoon Xtatic earphones that give a pretty good 5.1 sound (i use these on my 360), only issue I have is that you can't hear people talking that well with them. This is because you need to push the voice though the main channel (you have to set this up in your preferences to play from loudspeaker). Bit of an issue if you play with friends a lot.
These do take an optical input into their little converter box thing, I know as that is how I have them set up. They even come with an optical cable for that purpose. I got mine at a reasonable price from scan.co.uk.
Other options are (trying to remember the names):
- The Tritton Xtreme 360 which look exactly the same but seem to be more expensive, not certain about optical but would assume so. I have an incling that these are exactly the same as the Sharkoons but rebranded as Tritton.
- There are also some wireless Earforce X4's but no idea what these are like or if they take optical.