I've had lots of "advice" on this, where to get the cheapest etc. but as it turns out there seems only to be a few quid difference between the agents we went along to. We tried Trailfinders, Abbey Travel and the Australia Centre but everyone quoted the around the world ticket at €1555 ex tax.
We're going for a conventional seven stopper ticket with BA and Quantas however if you are doing anything slightly different and want to stray off this beaten path you might find a difference in price shopping around.