If you are looking for something with mobile internet (ie able to use the mobile phone system) then here are my comments:-
Don't buy a Telstra Tab as these are rubbish - underpowered and poor resistive touch screen.
If you are looking for a mainstream cheap alternative then the Optus MyTab is worth a look at the price, but have to say it is underpowered. While is has a resistive touch-screen it is actually well implemented and works fine.
If you are looking for a unit that you can hold in one hand (and yes, it can fit in your pocket - shirt or pants) then the 7" Samsung Galaxy Tab is a definite winner. I purchased one at $408 which I thought was a good buy but they are now available for less than that if you can still find them (Telstra had them for $299 online but has sold out). Very nice unit, (definitely not underpowered, responsive touch-screen, GPS works well) and honestly the 7" form factor is very convenient for portability but sometimes when looking at websites the 10+" form factor would be more better. But for me portability was more important, and I have no hesitation in recommending one if this is what you need, especially when it has come down to such a good price.
In the 10+" form factor, two very good units are being made available soon - the Samsung Galaxy Tab 10" (10.1V) which is the thicker version exclusively released to Vodafone (a thinner version is to follow later in the year), and the Motorola Xoom (10") which will be exclusive to Telstra. Both of these use the new Android (3.0 aka Honeycomb) designed more specifically for tablets. Obviously these will be expensive but if you can wait towards the end of the run you may find some good buying as with the 7" Galaxy Tab.
