Best 5.1 system for $100 ish

[lee3821]

I currently have the Striker 7.1 sound card and Logitech Z523 speakers. I'm looking for a 5.1 system that would run me somewhere in the neighborhood of $100.
One of my current problems is placement. My setup forces me to put my two front speakers in such a way that the left one is behind two of my monitors. It seems to me as though it is blocking the sound, and I'm wondering if a 5.1 system would potentially decrease the significance of that.
Anyhow, if you have recommendations for a 5.1 system that would sound better than my current Z523s and would cost less than $120, I'd very much appreciate it.
EDIT:Even if I'm playing two-channel music, the striker should upmix it to something that sounds at least halfway-decent, right?

 

[lee3821]

I'm currently looking at both the Logitech Z506 and X-540. Any recommendations?

 

[astrallite]

They are both pretty bad but I would go with the 506.

 

[lee3821]

They are both pretty bad but I would go with the 506.

Anything else you'd recommend near that budget? I know that a $120 or so limit decreases my quality, but is there something better than either of them?

 

[astrallite]

http/cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200506591620&rvr_id=142189607068&crlp=1_263602_263622&UA=%3F*F%3F&GUID=e3119b151290a0aad2448764ff9aefd1&itemid=200506591620%24&ff4=263602_263622

 

[lee3821]

http/cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200506591620&rvr_id=142189607068&crlp=1_263602_263622&UA=%3F*F%3F&GUID=e3119b151290a0aad2448764ff9aefd1&itemid=200506591620%24&ff4=263602_263622

Looks decent, thanks!

 

[lee3821]

Just bought it, hope it works well. Thanks for the recommendation.

 

[lee3821]

Best answer selected by lee3821.