Audio people? Sound cards, speakers and receivers?

[JT!]

So I'm kind of new to all this. After building my computer someone mentioned to me that I was missing a soundcard. Back then I was using a relatively cheap 2.1 speaker setup. I was skeptical so I ended up buying an ASUS Xonar DX used of ebay for what I was told was a good price. After installing it, I couldn't really tell the difference through the speakers. The only thing I could really notice was the absence of noise where it should be silence... which is kind of hard to explain.

I needed a pair of headphones so I bought the well rated JVC HA-rx700, seemed like they were the best rated for under $80. I bought these after I installed the soundcard so I didn't really have the integrated audio to compare.

Now that I built another PC for the living room (which I'm going to turn into a htpc) I realized that the sound on this is terrible, and really appreciated how much better the sound is with a dedicated sound card.

So what I would ultimately like to do is install a decentish soundcard in the living room pc and connect that to a 2.1 speaker system for the TV.

Polk bookshelf speakers and their 10" sub seem to be some of the best rated and I could probably get the 2.1 system for maybe about $170

I figure I'm going to need a receiver as I'll have two devices (tv & soundcard) using the speakers.

So my questions are...

Is my current setup on my pc (ASUS Xonar DX & the JCV headphones) a good match? Or is one bottle necking the other? Would it maybe a good idea to buy a better soundcard for my PC to use with the headphones and use the ASUS in the living room HTPC with the potential polk 2.1 setup? I use my pc and headphones so much more than I'll ever use the living room PC/TV which is maybe why I feel I should maybe upgrade? Or would that be a waste when I'm using relatively cheap headphones?

What do receivers actually do? These things cost hundreds of dollars, what do they do other than allow multiple devices to connect to one?

Pre-amps and amps? Necessary for my setup?

Thanks!

[HippY]

http://www.tomshardware.com/reviews/high-end-pc-audio,3733.html

Read this review through it is really interesting, especially read through the comments

I am not a sound guy (eyyyyyyy, i should receive some kind of PUNishments for my PUNny puns) as I live in a big family, and no one seem to like screamo metal and Heavy electronic music (sadly), but the best thing I can offer you is to do not use your front jack on your case, as the cable going through the noisy PC tends to get noise