Computer Speakers and sound card

[euphuistical]

I am looking for some decent computer speakers. Just used for listening to music, so one with a good sub would ideal. Looking for something mid to higher end.

Also I am currently using onboard sound (new comp, mobo has decent sound, not sure if I would notice the difference). But I do listen to a lot of music, so I can see it as a worthwhile investment. Don't really care if it would just help with gaming or mixing.

Thanks