G'day Fred,
If you buy the Eagle they come with the Nautic Path charts at no extra cost. These cover the whole east coast of australia and seem to be a reasonable sort of chart from what I have seen.
Also, they accept the Navionics XL3 Gold charts which cover all the east coast, and have the new green zones in them as well.
These cost around $370
Garmin use their own "blue" charts ... I dont think they have one that covers the entire coast of australia, so therefore you will be forced to buy 2 or more (depending on what you need)
You already know my thoughts on Navman
I assume you havent made a decision yet?
As I said in answering your PM, I personally wouldnt go past the Eagle 502 ... certainly a good unit, priced right, and free charts.
The Garmin is $300 dearer and you still have to buy charts on top of that.
Cheers
Pete