Like Dig said, there really are just two types.
But if you're talking about surround sound... I recently did some reading on it since I considered that so perhaps I can help you out a bit on that front.
First of all the first thing you want to decide is if you want to go Digital Surround Sound, or Analog Surround Sound.
Some motherboards offer a digital output port and some sound cards do as well. They're usually a small black hole that can't fit the standard audio jacks. From what I've read these usually have better quality but you'll want to run through an amplifier prior to connecting your speakers to it.
Or, if you get specific cards that are using the C-Media CMI8870 audio chipsets. Apparently they have some built in real-time processing capabilities that other chipsets do not have, or do not fully support.
Oh, digital surround support is usually known as SPDIF.
Or you can go Analog Surround Sound which is what most new motherboards have as well. I think they're... 5 audio jacks at the back? Left+Right, Center, Rear Left, Rear Right and Subwoofer or something along those lines. Those are much cheaper and much simpler, but of course the quality is also different.
It depends on your budget really. Keep in mind I did some reading but in the end decided against it because the SPDIF sound cards with C-Media CMI8770 audio chipsets are quite expensive. And speakers that have direct SPDIF in/out are also costly.
If you want to save money and yet have good surround for epic gaming... You might want to consider surround sound headphones. I've heard of some good ones in the past but I can't really remember them now.
Surround sound headphones also take out the possibility of disturbing neighbours and such if that's a concern.
Right now I'm just using Cyber Acoustics CA3550RB and even with my woofer set to lowest (it's got a strong woofer) my housemate can hear the "thump" in his room. Thankfully he's an easy going dude.
C-Media CMI8770 on Newegg