Sound Card : You can't really avoid buying this. Your main choice however is "on board" or a seperate sound card.

Both of these have their plus points. On board are certainly cheap. However, some may regard them as "nasty" also. The main problem appears to be driver issues. On the other hand sound cards can be "cheap and nasty" also. Some onboard soundcards can also provide problems when they eventually stop working. Can you disable it? The best advice I can give you in respect of a seperate sound card is to read as many reviews as you can. Bear in mind that the sound you get from your pc depends on three parts. The sound card, the drivers for the sound card and the speakers. In addition what do you want the sound cards to do? Do you REALLY listen to a lot of music, radio,T.V. through your pc. If so, you want a high end branded named card. If you only use the sound card to play the occasional windows start up wav file then you don't.

Equally if you purchase a good 3d card (you can purchase a creative labs for about £25) then you want to buy 3d speakers. You can spend a lot on speakers, but I recommend at least a 3-piece system (with a sub). You'll appreciate the deeper base and overall sound (especially if you are into playing games/listening to music). Otherwise buy a standard set of speakers (make sure you get independently powered ones and certainly NOT battery powered)