In my opinion, it would be hard to find something better than this: http://www.rme-audio.com/english/hammer/d9652.htm
I use this card, and it is definately top notch.
Runs around $700.00
It has 16 optical ins, and outs, and is expandable to 24 with the included expansion card. Availble in both Mac and PC versions. PC version is supported by WIN98SE, WIN2000. It is not supported by WINME. At least I don't believe it is.