g5 / 5.1/7.1 sound decoding

[Avijit Ghosh]

	Hi all I've decided to make the "switch"  and  just ordered a G5 
which is coming in a few weeks. I'm a bit confused w/ regards to what 
audio speaker setup I should get for multimedia sound. If i'm going
to spend ~$200+ I feel like I may as well get the current standard
to last me the lifetime of the machine but I am a bit confused
to what the G5 audio system does. 

My understanding from the apple store is they recommend the Logitech Z680
system. Does this mean that the g5 "sound card" does not do digital 
decoding on board and is using the Z680 to do the decoding? Does this
mean that the G5 is equally capable of doing 7.1 since it is just
passing through the signal output from the dvd player? 

Will a 5.1 speaker system w/out a decoder  work on the g5 (i.e. many of 
the creative lab/cambridge speakers?)

Will a 7.1 speaker system w/out a decoder work on the g5?

What would be the recommended setup for doing proper 7.1 on the macintosh?

(buying the m-audio card or is this redundant?)

	best regards,
	-avi