[QUOTE=Brain Wreck]
I’ve got an Audigy 2, which I figured was a modestly price but decent card, should that be sufficient?
I guess I’m puzzled to hear that there could be that much difference in sound cards. Compared to something like graphics cards, which are like little computers in their own way, I figured sound cards were basically a commodity item at this point. so is there a big spectrum of quality in sound cards?
[/QUOTE]
Point of fact, sound cards are “litle computers of their own” 
Now, I am not going to argue that if you want the absolute best in sound from your computer, nothing beats hooking it up through a high-end hi-fi amp/system as was mentioned upthread. There are simply limits to what a sound card and self-powered speakers can do – size, for instance, having a lot to do with it.
Having said that, again, much depends what role you want your computer audio to play in your home and just how much of an audiophile you really are. For instance, I have my dektop computer in my room, and as I said before, whether for music or movies, I am more than pleased with my set-up – I hardly need to crank my speakers more than half way – and that’s just for DVD’s which need more volume anyway. MP-3s and CDs sound just fine with little more than 1/4 to a 1/3 of the total watts I have available – unless, of ocurse, I was having a dance-party in my room. Not something I’m known for doing.
For that, I have a whole different Home Theater rig – which as I mentioned before, I just upgraded from my last unit which was coming up on six years of use. No need to go into the particulars of that system, but let’s just say that if I really want to crank my audio and/or watch a rental DVD, a 62" DLP screen, along with a 7.1 speaker set-up pumping out 1200 watts, will make my desktop rig sound silly.
So, you see, its a matter of scales.
In closing, if you use your computer like me, and just want good, solid sound (not “audophile” class mind you), I really don’t think you can go wrong with the Logitechs or the Klipschs that have been mentioned here.
As for sound cards and what they mean and do to your computer sound, here are a couple of articles that might help you understand their function a bit better – and by the bye, if your Audigy is a PCI card (not onboard), I think you’re fine sticking with it. Solid card all-around if not top-of-the line anymore.
Anyway:
SOUND CARDS
Hear It All with Surround Sound