Sorry for short reply earlier but i was in a rush, a more detailed response for you:
The Go1000 Live UK, Go1000 Live European, Go1005 Live UK and Go1005 Live European all suffer from a lack of ability due to the "MyTomTom" PC interface, this is currently preventing users from purchasing maps or adding certain content to the device. As you mentioned adding the Australia map to the unit I wouldn't recommend these units at the current time. An update to the software at some future point should re-enable the missing capabilities but I wouldn't try to second guess when any of the missing features are to be introduced, TomTom have advised as to when they aim to release certain functionality but whether they acheive these dates is another matter.
XL_IQ_Live is a very credible device but being UK based it will be missing Text To Speech and doesn't have the necessary memory card expansion slot, whilst its possible to swap maps about for a trip to Aussy its a bit of messing around you could avoid with a better device.
750 Live includes all you need and is supplied with European mapping, to avoid messing around with the new zonal European maps the memory card expansion slot is very handy indeed but this does mean purchasing a memory card in addition to the device, if you don't intend to use the device in mainland Europe then the next item will be more suitable, adding the Aussy map to the 750 Live will require the use of a memory card.
550 Live includes all you need and due to the available memory within the device you will get away with the UK&ROI map as well as the Aussy map installed without needing a memory card. The device has a memory card slot though aiding future expansion if/ when required - Mike
