canada16:People who buy the 10.1 or 9.1 usually have the 9.0 and 10.0 for the surround
My 5.1 system has 9.1 front and 9.0 surround.
The 9.1 speakers in my system are also used for stereo listening (via the pre-outs on my home cinema amp) and are superb!
I originally had 9.0 front speakers and, although they too are superb little speakers, I found them a little lacking in bass (although I am not one for room shaking bass and my room is only 13 foot sqaure).
The 9.0 are great for the money, especially for the crazy £39.99 I've seen them at RS, but I have definitely seen an all-round improvement in the sound and enjoy stereo music so much more with the 9.1 speakers.
Defintley well worth paying that little bit more for the 9.1 speakers as far as stereo use is concened.