Using AMD gives more bang for a buck - It's simple as that.
Erm... not release updates? Uh, oh... you may want to think that statement again...
Next OS? There's one candidate on it's way already, but it's still a long way from being ready.
No, it's not a next version of your EyeCandyXP...
Where did you got that misinformation about A64 not being able play more than 2 channels? Are you sure you did not get
audio and
memory channels mixed up?! It would not makes any sense to put 8 channel (7.1) audio to on-board, if it could not be used...
Even older "small" CPU's can handle multiple audio channels well, depending about audio card/chip...