i have the audigy 2 zs
firstly yes that card is very very good i have been very pleased with it
as for speakers ive had the T7700 and now go the creative gigaworks 7.1 THX
the 7700 are okay but when u listen to the gigaworks 7.1 system in comparison with the same soundcard and all it just plain blows them out of the water not just by a little bit but by leaps and bounds and i dont mean just about power i mean bass reproduction and sound quality the lot
however i had a creative 5.1 speaker system in my last computer with an audigy 1 card and that was good but i found a whole new level when the T7700 arrrived and the audigy 2 with my new system. so yes i would be very happy if i had stayed with the 7700 but if i had not heard what the gigaworks are capable of
i dont know what the difference is between the 7900 and the 7700. i know the 7900 is newer but it costs slightly less the tech specs on the website say bugger all different
if you chose the creative system i would choose the 7900 purely because its newer and maybe its just a release to fix some small errors which were present in the 7700 as i said the tech specs look identical
i found as i was very very very happy before with the T7700 and it was excellent for everything i threw at it i did not realise i was missing anything till the day the gigaworks system arrived here
my advice is get the ZS as its a brilliant card and then try to stump up the money the gigaworks system
here is a good review of the gigaworks paired with the ZS
to cut it short they say
"The Gigaworks 7.1 by itself are truly good speakers, in my opinion even the best 7.1 computer speakers to date that I've run into, why you ask? No one other than Creative has 7.1 computer speakers. The only set I can think of right now is the Inspire T7700 7.1 set, oh and hey .. Terratec has a 7.1 kit now that I remember it, yet it's no match for a high-end set like this at all."
"Bottom line: You'll pay a lot of money for a product of this caliber, but if you can spend that dough you really can't go wrong with it. An Audigy 2 ZS is a must have with these speakers though !"
they also have the 7700 reviewed there here is the link
if not able to get the gigaworks id say the 7900 is a good buy and definately a much better price