That's a mighty fine sound card. How about starting with 2.1 or 2.0 and adding the rest later? For 2.1 you could go with a pair of Audioengine's or A5 or A5+ for $300-400/pr depending if you catch a good deal. Or Behringer's B1030A for $142ea. Both are powered speakers and won't need an amp. Add a subwoofer and you're in good shape and then just add additional speakers as money allows. I'd try to find a local store to test them and see what you like. I'm not sure who carries the A5 but I think some Guitar Centers carry the Behringer.
It'll take you $100 over budget but a $320 Hsu STF-2 would be a decent sub for a room that size and not too huge - Hsu makes good stuff. I've never listened to a Bic F12 but they have a decent rep for a bargain basement $200 first subwoofer but again I haven't heard the Bic and can't endorse it.
Ah, I see that it will be harder to fit quality speakers into a $500 budget if I go 5.1 to begin with. Starting with 2.0 and going to 2.1 and 5.1 later as you suggested would indeed give me the best bang for the buck in the long run.
I've looked into the powered speakers you mentioned and have a few questions if you or anyone could help me.
Do you think the Behringer MS40 wouldn't be worth it compared to the B1030A or B2030A?
Also, the Audioengine 5+ and the Behringer MS40 seem to come in pairs where one side contains the amp and power cord connection. So how would I add a center speaker if I want to form a 5.1 setup later, provided I don't want to mix and match speakers from different companies? (the NHT SuperPower also seem nice and appear to be sold in single operable units as opposed to pairs. maybe I can use these for my purposes?)
Are 5.1 setups usually only done with passive speakers?
Having 5 quality active speakers and a quality subwoofer for my PC with a high end soundcard seems like a really cool idea, but I just can't figure out how the power cords would work in such a setup. Would I have 6 power cords each going into a speaker and the sub? Or perhaps 4 power cords(front, rear, center, sub)? Sorry I'm such a newbie, haha.
Oh, and another thing that has been confusing me the last few days: if I were to get passive speakers, do I need both a receiver and an amp? or one of the two? The only thing I have to connect to my speakers is my computer soundcard, which already has a DAC. So a receiver with all different types of inputs and decoding features seem kind of pointless to me. Is it possible to have just an amp and no receiver for a 5.1 setup?
If these questions sound like I have not a clue as to how audio systems work, it's because I don't! lol Don't laugh at me!