Sound card quality

[benhar]

I have been contemplating upgrading to a newer sound card, but haven't decided yet. I am still using the 64 voice TBS Montego that came with my Dell in '98. I haven't heard any of the newer sound cards firsthand... how noticable is the difference between the newer cards and the older ones in applications such as playing MP3s? Considering the fact that I am only a casual gamer, is the difference worth paying $130 for a new card? (if I get one it will be the Hercules GTXP)

Thanks