the turtle beach is good (i hear) costs around the $70 or so (are you in the states??)
the thing is, as much as i dislike them, the soundblaster live player 5.1 oem could be fine for your needs (just important to not install ALL the crap irritating software that comes with it)http://www.ciao.co.uk/Creative_Labs_Soundblaster_Live_Player_5_1__Review_5327557
thats a review i found.
heres a good one for the turtle beach santa cruz:http://www.neoseeker.com/Articles/Hardware/Reviews/santacruz/
certainly seems a good card.
depends how much of an audiophile you consider yourself. and if it is mostly for listening to mp3's etc, then you arent going to be missing anything by getting a lower price card.
hope this helps.