The receiver i got is able to output 7:1 so check out Part One - The Receiver if you haven't already and want to take a look at it. The speaker system i also from Sony (in fact everything is!) and is their SAVS300 series. I couldn't really find any decent imagery of it in situ online so will be posting up some real pictures once it arrives (tomorrow!).
The big ones go at the front, the wee ones in the middle go at the back (there are 4 speakers, and you can split them in two to get 7:1 sound). The flat one is the centre speaker, which will sit under the plasma unit, and the fat one on the right is the subwoofer, which will bumble away in the corner of the room. The silver things on the right are stands for the wee ones in the middle.
Part Three - The Vision (and video!)