Nice looking speakers!!
I got me a good deal on a sound system, it was really kinda luck, but i have a pair of CAT speakers, each huge, taller than my waist hight, three cones in each with a bass hole in than you can shove a can of deodrant down.
That hooked up to my Realistic (Dads old) 20 year old stereo amp, then plugged into my computer makes for an AWESOME sound system, at a cost of £35 (for the pair of speakers which were my best ever bargain, from Lidls as it happens, and the cables/adaptors.)
So it's not surround sound, but hey. Its awesome. I can make my sisters pictures fall off the wall and the walls shudder with my bass. The qualitys good too. I think you can see the speakers behind me in my avatar.
The logitech ones look real nice though, they will definatly be awesome quality. I had a budget logitech sound system before my current one and it was great.
A good reccomendation by Quad, and a good choice by yourself, by the looks of things