Sound Card...

If you are planning on really using your computer above simple E-mailing, from watching movies to listening to music or serious gaming, I'd recommend buying a PCI sound card, especially one that supports such standard audio formats like Dolby 5.1 Digital Surround Sound and THX. Generally, a motherboard's built-in sound supply will not support digital standards like Dolby's and attaining full surround sound can be a sketchy proposition.

If you decide that you will need a PCI soundcard, Creative Labs-brand cards are the clear choice. Creative Labs is the leader in the computer audio field, with the more recent Soundblaster Audigy series and the Sound Blaster Live! 5.1 card. The Audigy is the clear winner performance-wise, with higher bit output and higher kHz range (and allows you to digitally connect to external sources, like an existing Bose system), but the Live! 5.1 card still performs remarkably well (and has performed very satisfactorily for me).

 

How to build a computer - Creative Sound Blaster Audigy Gamer Retail Box   Sound Blaster's Site

While the differences between the Audigy and the Live! 5.1 cards are significant, to fully realize their potential you need to make sure to purchase speakers that can fully utilize the digital/surround sound that these sound cards can emit. I've been very happy with my Altec Lansing 251 speakers that I bought, but I recommend any speaker/subwoofer combination that Altec produces. Here's a gamer's perspective on the Audigy card, and here is a more comprehensive review of the card.

Speakers 

For speakers, I recommend you purchasing at least a 3 speaker system (2 satellite speakers and a subwoofer). This realizes a much better sound versus a 2 speaker system and is definitely well worth the investment.

A 3 speaker system is also sometimes listed as a 2.1 system, as it has the 2 satellite speakers and the subwoofer. To achieve true surround sound, you will most likely need to get a 5.1 system (5 satellites and a sub), and I know that the speaker systems go up to at least 7.1. If you plan on having an elaborate game setup or plan on using your computer speakers in a TV setup, you should consider getting something more than a 2.1 setup.

If you plan on going for a surround sound setup and plan on purchasing the necessary speaker system, make sure that your sound card supports the 5.1, 6.1, or whatever type your speaker system ends up being.

Headphones

Headphones can be a cheaper way to realize a rich sound experience. They are relatively cheap compared to an elaborate, expensive speaker setup, are portable, and can provide the same 'surround sound' experience which may be required for gaming, TV, or whatever.

I currently recommend a set of headphones that are 'noise-cancelling'. This recommendation comes after I lived in the dorms freshman year of college and had to live with my roommate watching TV (particularly 'Survivor') nearly 24/7. With technology out there allowing you to cancel out extraneous sounds, allowing you to actually enjoy what you're listening to, why not go for it? This technology is not for the rich and famous anymore; it's actually competitive with the traditional headphone technology.

Here again are my complete recommendations for building a computer with a great Sound Card at a low price!

Next - Hard Drive Storage »

 

Tip: Unless you are an extreme audiophile, I would not expect you needing to spend more than $100 on your entire sound setup, with ~$20-$40 on a sound card and $60-$80 on a speaker setup. I generally recommend Altec speakers and CreativeLabs soundcards.