Looking for a good speaker setup, more details inside.

Alright, atm I currently have a logitech x540 setup, which I use with my tv for gaming and television (Matrix Mode) and use it with my computer with only using the 2.1 setup (as I've heard it sounds better, and I'm not sure but I think using it with only 2 speakers increases the output of the the 3 devices at work, then having all 6 being used, I'd also like someone to confirm if 2.1 is better then 5.1 for music and if I am right about output for using just 2.1 rather then matrix mode 5.1.

I have a late 2007 imac, but I am willing to buy a usb sound card if I have to.

Alright down to business, I am looking to get a better pair for my computer. The 5.1 on this system in my opinion is already good enough for gaming, so I may just keep it plugged into my tv, however, I would like a better *Music* setup.

So my questions are as follows:

My budget is atm $400 but if shown good things, I may consider raising it.

Atm I am considering keeping the x540's and buying some z2300's for music. I have also considered selling the x540's and getting some z5500's and use them for everything.

Of course, being that this is head-fi I'm asking, I am almost positive that logitech will not even be recommended in the slightest (although I like the quality of the x540's for the price =D), my question is, is there any better setups? Should I do 2.1 or 5.1? Soundcard? any suggestions would be great.

I would consider myself an audiophile, however atm I'd rather not pay alot of money for a until my life ends setup xD. If it at all helps, my current headphone setup is my shure 750dj's, and I think they sound fantastic.

Ok a bit more specific.

I love bass when it comes to a good system, however I would rather it not be muddy as I appreciate flat sounding much more over over bassy.

My Genres are as follows in order:

Post Hardcore

Melodic Metal

J Pop

Piano...I guess xD

Whatever style gorillaz is considered

OST's (I love listening to these)

So atm I'd prefer a set that would be greatest for melodic metal (like dark tranquility and such) however I listen to alot of JPop so that would be good to.

I guess my final addition before you guys start suggesting is I love to watch anime, so although I love the 5.1 when it comes to anime, and I love the bass drop whenever  theres like a shock scene or a break down scene, so I wondering if I should use my x540s for anime 5.1, or you guys got a 2.1/5.1 setup that also includes this too (potentially making my x540s only good for xbox, unless these other setups replace that to xD)

Alright thx, I'f I am a bit confusing somewhere Ill clarify if you point it out, if you need more info I'll respond.

OR, do I scrap all my current thoughts and think of something completely different rather then pc speakers... I know about companies like definitive but I just don't know where to start.

Thank you for your time.

- Khaos

Alright, It would appear the swans are better then the audioengine 5's right? If I go with them what reciever/sub should I get to go along with them, after I buy the whole set I don't want to use more then $500 unless I have to, or if its just so worth it to go over, then I will

Edit: Considering getting the stf-2 unless people say the vtf -1 is better.

EDIT: Oh and I assume I also need a reciever, what should I go for? I'd love to use this mostly on my iMac however being that I am now getting almost the full package I might as well also say my TV (I may consider connecting it to my tv, and then have my pc send out audio to my tv's audio in and vice versa),but on the other hand being able to switch between my macs toslink and my tv's anything would be great (I have a led 40' samsung)

Is this good or is it not strong enough for a reciever (Considering the sub im getting): http://www.amazon.com/Onkyo-TX-SR308-5-1-Channel-Theater-Receiver/dp/B003BEDQQM/ref=cm_cr_pr_product_top

I'm new to this so I don't quite understand it all, thank you