Using a comp as a reciever?

[Homura]

So I have just emersed myself into the world of HD and I am loving it. I went in 3rds with two of my brothers and picked up the ps3 on release day (we always go in on shares with all our game systems...starting back when the ps1/n64 came out). Being that I'm away at college and my other two brothers live near each other back at home, we tend to rotate the systems between each other, but they are good about leaving me with the ps3 since they have the wii and 360.

After saving and contemplating for quite some time, a few weeks ago I finally decided to buy a projector to watch movies and play games on. Being that I am a college student at USC, and am starting up dental school here in August, it took a little bit of time to save up my money. I ended up getting the Panasonic AX200U 720p and could not be happier (there was no way I could afford a 1080p projector).

Having a legit display, and a legit player, my next task is tackling my audio. As of right now I have all my audio running through my computer (that I built...wow it's been 3 years already) in a creative audigy 2 zs sound card. I am using an optical cable into my board and am running the audio through a pretty cheap logitech 5.1 system (under $100). So where do I go next, or is what I have running fine for BD displaying at 720p. Two of my roommates have hd setups (1 with a new 40 inch samsung and crappy horrible functioning Sony reciever (IMO) and ok sounding yamaha speakers; the other with an Onkyo 605 7.1 system on a 50 inch Olivia 1080p screen). When I compare what I have set up with how theres sounds, I honestly feel like mine sounds better.

I know half of the BD experience is the video and the other half is the audio. I could not be happier with my video, and am pretty happy with the audio; the thing that bothers me most is that it is really difficult to get the speakers into the corners of the room to give a real surround feeling. Am I going to get much of a better audio experience for under $500-$1000 or am I just better off saving my money for the next 4 years through dental school, and maybe a few out of dental school, and then splurging on a 1080p or 1260p system by then with a couple thousand to spend on audio? I've been looking at other posts on recievers/speakers and seem to read that onkyos are the way to go, or yamahas, or waiting for the new pioneer. If you guys think I need a receiver/new speakers, would you mind sharing your thoughts on what combo. Thanks for your thoughts.