LOL! But man-amp ratings are everything!!!
I played with a set of 680's at a store a couple of weeks ago and was fairly impressed. For the money they are very good speakers but I came away thinking they were a better version of the Z-560's instead of a better version of the Klipsch 5.1's.
I love the bass of the Logitech's 560's for gaming and felt the same about the 680. But what I didn't like about the 560's carried over, too. The midrange is warm but lacks definition and presence. Same for the high end reproduction. It seems like everything coming out of the satellites is just along for the ride. For gaming, that is more than good enough but there are much better choices for music and movie work.
I can't put my finger on the exact difference, but the Klipsch 5.1's do have better overall sound quality than I remember from the 4.1's. (I haven't heard them side-by-side.) It wasn't harsh or metallic. But what really struck me about the 5.1's was how they handled positional audio. These are very good all around speakers and hands-down the best for DVD's.
My first priority were speakers that could reproduce music, and I ended up getting a Monsoon MM2000 4.1 system. These use the planar satellite design with a three speaker subwoofer and a 200 watt RMS (I think) amp.
What I love about them is the crispness and clarity, especially in the midrange and high end. They are clearly more accurate and detailed than the Klipsch or Logitech. The downside is that while they have a great presence, they aren't great on positional sounds like the Klipsch, and the bass doesn't try to give you more than what was put into the microphone. On gaming they bass is good, but not nearly in the class of the Logitech.
Hope this helped-
BHD