I think getting a sound card is worth getting.
I've had 3 cards in my time. One was an old AWE64 card that was actually pretty good, then a Sound Blaster Live, and now an X-Fi Xtreme Music.
I have to say, even though its good, I want to get into more music production now, and the card I have doesn't even offer a MIDI input, yet, my older Creative Sound Blaster Live card did.
It also doesn't offer Optical Out. Something I really want now with these new speakers.
So I may sell this card, and get a more production based one.
Or is it possible to have 2 in one system? Or a card with just MIDI in's and Optical Outs that link to the sound card? Doubt it, but worth a try