There's heaps of them around with Sat Nav and GPS and Bluetooth - can anyone recommend any particular model as being okay for the money?

a brand name you know of. otherwise just plain no. a goo way of telling if its a piece of crap is if it offers lots of features and has a really cheap price. generally that works.

I recommend buying from Hong Kong. Got me an Alpine iDA-X100 for $318, which will likely be $599 if Alpine ever puts it on their Australian website.

The reason we have an Ebay Only Thread (http://www.aussiemagna.com/forums/showthread.php?t=59591) is because most of the stuff on their is junk, and if you are buying a brand name product it's generally factory seconds or at the very best a shotty grey import that you wont get an australian warranty with.
Support your country, support our economy, buy local.