The difference between a $100 and $200 sound card is not very noticeable. You're just paying for the latest technology which costs a lot to produce, but doesn't produce what it costs, if you get what I mean.
I personally have a X-Fi Fatal1ty Xtremegamer that I found on clearance at Best Buy for $60, that's a steal considering their regular price of $160.
However, I upgraded from a Soundblaster Live! 24 bit and although the sound quality is noticeably better, I can't see someone spending over $100 for it. So, my point is any decent sound card will be fine, you don't have to spend that much money. I recommend any of the X-Fi cards.