Thanks for the reply but i was a bit vague with my question.
I listen to everything from my pc through my receiver, and i realise this is a pretty dumb question but some things i've read seem to suggest that any card that has Dolby Digital Live encoding will pretty much produce the same audio quality. So though DDL the trust card will be more or less the same as the X-Fi.
I guess i'm asking whether the X-Fi card will be worth upgrading from my trust card, if i listen to everything through DDL and my dolby receiver.
It seems likely it would be better with the expensive X-Fi card, but I read a few things that worried me a little, and thought i would just check.