I bought these speakers from Amazon for 149.99 w/Free Shipping. They are great, clean, clear mids/highs and very good Bass, almost too aggressive sometimes, but I believe that is a trait of Logitech speakers in general. I paired them up with a Sound Blaster audigy ZS Platinum and couldn't be happier with the sound or the amount of money I paid! Wall mounting is really simple, just be advised that the center channel cannot be mounted. I highly reccomend these and don't really see a reason to by the Z-680's over these unless you need the DTS/Dolby Digital decoder built right in to the speaker set.
If I had to rate them on a scale of five, I would give them a 4.5!
Also be advised that the sub for these speakers is massive, and I do mean massive, it is almost bigger than the Onkyo I bought for my home theater!