If all ur gonna do is listen 2 ur MP3's u've dumped off the internet, and ur not a fussy listener, then ur ob snd will b fine with ur little speakers. However if ur looking for something a little better, without a great deal of outlay, I'd recommend Creative's Live 5.1. It'll cost u about 40 bucks (I think... I'm from Australia, there's about AU$2.00/US$1.00). Then if u decide ur speakers are holding u down you can go spend $100 on something more decent.
Another thing u may want to consider is CPU usage. If u've got an old system then ur snd card may make a great difference to system performance, I know it does to my PI133 laptop!!! El Cheapo cards would be less efficient I'm guessing, but... you get what u pay for (most of the time...hopefully). ...Hmmn, I read about a card from Phillips that was supposed to be pretty efficient...
But if u've got a PI266 CPU or better then u'll have absolutely no worries whatsoeva.
I'm planning on putting up with AC'97 ob snd, pumped through my Phillips stereo speakers until I've saved up for an Audigy and a set of Hercules XPS 510 speakers
....hmmm, yeah....
It's alive!!! hahahahaha!!!