Audio On Macs, help, advice, sanity?! Options

[sparky-m]

i was wondering if theres anyone who could offer some advice,guidance or sanity!

Well, here goes,

I want a mac for audio music production purposes and to add electronic sound on top. I don't really need to record onto tracks, just to be able to download tracks from a yamaha aw4416 hardisc recorder and have flexibilty with them. I've heard the cheap pro tools is the best for audio, but am i right in thinking i don't need a 'break out box' as i will not be recording to the hardrive? or is this bollox?

I was thinking of an G4 imac due to funds would this be ok?
Any ideas on any other software would be greatly recieved!
As I've never used macs before, is there a quick way to get pre recorded audio onto the hardrive.
Does anyone know if its possible to hook up the yamaha aw4416 to a mac!!??

ANY help or advice would be appreciated

Thanks in advance