Waaaaahhhh....... I had made a very very very loooong post here....
It is all deleted!!! Damn you admins
No patience to post that again. Had taken all the info from Creative webite and hosted images at Imageshack....
Anyway, when it comes to sound quality, the Klipsch and the CReative MEgaworks 5.1 550 is better than the ?Logitech mainly because of thr bass. While the 5500 has amazing bass, some reviewers feel it overpowers the acual music. They find the bass too boomy.
But whren it comes to an overall package, the 5500 wins because of it's digital inputs and Decoder. But nt many people use the digital inputs and the decoder on the Audigy 2 ZS is better. So, it is better to connect it to your Audigy 2 ZS by analog itself.
And if you plan to buy it from India, then the Creative 5.1 550 is the only other option you have as the Klipsch is waaaaay too expensive. Around 37K(I read somewhere on TE. SOmeone else had posted). The Creative Megaworks 5.1 550 is around 25K. Not worth it to pay 15K for just that little bit extra for the Klipsch brandname...