If you read any mags, you will find that alot of people are getting pissed in the computer industry, because a relatively cheap ($300) set of speakers from altec lansing sound better than their $1500 home theater system. The altec lansing acs-500 speakers are a favorite among "power gamers" and "multi-media enthusiasts" because they sound better, and put out more bass than alot more expensive home stereo systems. Most of the people they talk to that use these speakers do not use their home theater systems much anymore for playing cd audio, because the altec lansing speakers sound better. But unfortunately, this is not a good choice for a 2-8 speaker output sound card like the sb-live. If you want a good 4-point sound system, the cambridge soundworks pc-works 4-point surround system is an excellent choice for your sb-live card, as it has controls for front and rear chanels, comes with 4 sattelite and 1 subwoofer speakers. This will also cost significantly less than 2 amplifiers and 4 speakers from a local hi-fi shop, plus it will give you good control over front and rear chanels. You could also go the single amplifier rout and 5 speakers with a dolby prologic reciever, the sb-live now has a patch that outputs surround sound to a dolby reciever the standard way (through 2 rca cables). From what I have heard though, this does not get as good 3d positional audio sound as the 4-point surround speakers from cambridge do.
As an audiophile I have to say that the Cambride Soundworks Microworks set of speakers is anyones (who is looking for the best sound) best choice. They are expensive and they are only 2 speakers plus the sub, but they sound better than any home stereo in the price range. My Bose home theatre doesn't come close to the repose and acuracy of these speakers. For a 4 point speaker system I recommend the Cambridge 4 Point system because they have great sound and a great price, though they are not as loud and don't quite sound quite as good as the microworks.
The best speakers to pick are the ones that sound the 'best' to you. Since you are the one that has to listen to them when you play games or any type of audio. I'd say use your ears and pick the ones that you like the best. One other thing... if you're looking for 'loudness' pick the ones that have the highest RMS rating and sound the best to you.