Best audio set for PC with 300-600€

Hi,

I have a SoundBlaster X-Fi Platinum Fatal1ty but my speakers kinda suck right now so I want to get something better.

I also have a HDTV 32" connected directly to the PC via HDMI so I watch a lot of movies in 1080p with DTS sound in the PC...

To sum up, my use would be:

45% HD Movies with DTS
35% Dance (House, techno) Music @ MP3 320kbps
10% Movies with AC3 (DD)
10% Gaming

I can spend 300-600EUR, depending on if its worth or not spending more...

As PC Speakers I've seen that the best are Creative GigaWorks S750 or the Logitech Z-5500, but some people says that for this money it would be better to buy a low-mid quality home cinema set, with an amplifier and all that stuff... But I'm totally lost about that systems so if you recommend me so tell me what would you buy

I have to say that my room it's like 3x4,5 meters, so the max distance to a speaker would be like 2m

BUT, I'm kinda freak with technology so I don't care spending more money if then I will get a better experience with a better sound and more power.

Thank you very much guys (and ladies )

I went to a shop to ask about the logitech and they told me that probably logitech is going to launch a new version, because there wans't any z-5500 available in any of his providers.

Then I started looking at hifi sets and found this:

Pioneer VSX-819 H-K (330€) or Pioneer VSX-519 V-K (230€)

and

Pioneer S-V50N-K (250€)

480 or 580 in total.

What do you think about that set? It would sound better that the logitech?

This is one of the best site for sound system reviews.
http://www.whathifi.com/Reviews/