I am new to the home theater/ audiophile market.
I went ahead and purchased some X-540s from my z-640s, which in my opinion is quite a large let down besides games, which I think they fit the bill just right. These are alot quieter then my z-640s (even with daniel Ks driver mod), and just don't fit the bill for my mp3s with average 320 kbps bit rate and sound like god ran my music through a meat grinder.
After doing some research, I found that there isn't alot 5.1-7.1 of speakers home theater below 1000 dollars, so I am looking into more of a conventional 2.1 speaker setup exclusively for playing music.
My budget is 300 bucks, and I'm not against buying used as I think this is where the value is at.
I'd rather stay away from actual computer speaker setup as I would like an upgrade path with these to a home theater setup later on.
These will also be for an apartment so I don't want bass too boomy as I would be using my x-540s for games (20 dollars in shipping doesn't justify returning these 75 dollar pieces of crap), I'd rather like a complex treble sound as I listen to complex progressive metal and classical music with alot of different instruments being played.
I like the idea of a bookshelf kind of speaker system as I hear these produce the best 2.1 sound.
Also what kind of receivers would I use to connect to my computer? I'd prefer to be able to switch between my x-540s, and these. I'd also like a way to hook the receiver up to my tv so I would be able to use these speakers on my tv, but then be able to switch back to my soundcard on my computer. These won't be part of my budget but would like to keep it low as I'd rather spend more money on a speaker system then a receiver.

I've looked at Elemental Design, Klipschs, and even B&W, but I don't know nearly enough in what I should buy to make a decision.