That's hard for me to say.
I'm not really familiar with lower end sound cards.
I have an Audigy 2 ZS which runs for $75 and I use it for my Klipsch 5.1 Ultras which are slightly better sounding than the 2.1s (+3 channels aside, the sub is much better).
I've heard many people saying that the sound card is very important with these speakers.
If you play games or listen to CD audio or higher quality then I disagree. There's a big difference.
If you're talking about internet browsing and mp3s, I agree.