My brother has the T6060 set and hates the way they sound, he will be changing them as soon as he can. I've heard them myself and it's true, they're really unclear and badly balanced.
The S500 set may be a little better, but will not be great by any means. So there are 2 questions; do you really need surround sound? Is the primary purpose gaming, or do you play a lot of music? And; could the budget extend any further? See, you only get decend sounding surround for over £100 unfortunately. You could get a decent 2.1 set for less of course. How do you feel about headphones?
We have a 4.1 set, Cambridge soundworks, down here. It sounds significantly better than the T6060 set.