I hear the Sound Blaster X-Fi XtremeGamer
is the sound card to get. Though, I hear *all* sound cards are having problems with Vista, so if you have Vista, maybe you should stick with on-board audio for a little while.
As for speakers, I couldn't help you there. I, personally, would pick up more Logitech ones. The Logitech G51 5.1 Speakers
are Logitech's newest, but they come with a hefty price tag. You could also check out the Logitech X-540 5.1 Speakers
Like I said, for speakers I generally just grab something recent from Logitech. However, for the sound card, that Sound Blaster X-Fi XtremeGamer
is supposed to be hot stuff.