Digital Navigation

You will need a bluetooth or usb gps device for the laptop if you want to see where you are in real time.
http://www.ebay.com.au/itm/Holux-M-241-Bluetooth-GPS-Receiver-G-Mouse-M241-GPS-Data-Logger-ezTour-Software-/281840030844?hash=item419ef9947c:g:gCoAAOSwRLZUBo-D

Your cheapest option for maps is the free Memory Map application you can download from their website.
http://memory-map.com.au/mapping-software.html

You can also get free 250k maps for all of Australia.
http://www.ga.gov.au/scientific-topics/national-location-information/topographic-maps-data/digital-topographic-maps

The reason I suggested Memory Map is because it is free and works on Windows laptops, Apple iphones or ipads and Android phones and tablets. You can buy the Hema map set for it and the same maps work on every platform.

Beach, my thoughts are that tablets and Laptops take up a lot of room in the front of the vehicle. I would cut to the chase and buy the Hema HN7 7 inch GPS and load it up with maps. You can still do all your planning on a laptop and then load way points & POI's to your GPS. I run a Garmin by the way but the Hema HN7 is probably the most used GPS on the market and gives great detail plus easy to use.

Beach40
Personally, if I did not have a tablet, then I would just get the Hema 7 navigator. Too messy on a laptop, putting it somewhere (where?), keeping it charged (messy connectors to get to 19V) etc.
If you have a tablet ok, not messy and easier to handle.
CJ

Many folk want an all-in-one package and that's understandable. But it's important to be aware that there are three parts to the tech: the hardware, the software and the maps.

If you go for a tablet or laptop you are free to choose the best maps for your purpose, and that really should be your starting point.

The OPer might be happy with vanilla street maps in which case any of the standard GPS packages will be fine (and can be surprisingly good for tracks too) costing $100-$150.

The big issue with hardware AFAIC is screen reflection and brightness, and the Hema Navigator 5 I had was hopeless there and also phones and tablets with glass touchscreens can be poor performers in bright light.

My advice if you want something straight out of the box is to go with the Hema HN7. You get the latest Hema maps and a version of OziExplorer. You turn it on and use it and it should be reasonably intuitive to use. It also has street navigation for towns. No its not perfect but as good as you will get.

In my opinion Hema have the best maps available for Australia, both in coverage and accuracy. No map is perfect but again you are not going to get better.

I personally have the Hema suite of maps that I run on Samsung Galaxy Tab3 7 Lite using Oziexplorer for Android. They are the same maps as above but a more hands on arrangements. I also have the EOTopo maps from Exploroz that I see great potential in, but at this time I think the Hema products are better. For my setup I need the PC version of OziExplorer too because but I like to do my own thing are far as waypoints and tracks are concerned.
WBS

Hi, we use an IPad mini (cellular version) and found it useful for the other things you can do, ie emails, photo's, Internet etc. Currently we are 7 weeks into a 14 week trip.

Four apps we use daily are;

Hema Explorer - record daily track and zoom in to street level when arriving in a new town. Need mobile reception for the street view but seems Telstra is now everywhere and uses very little data when downloading street level.

Hema 4wd Maps - current range of all maps for Aus. Downloaded on the device before we left. Found with this app you have a choice of maps for the one area, ie when in Kakadu, you have actual map of Kakadu, also Top End, Gulf Country, Northern Territory as well as the Aus topo 1:250. These all offer different levels of detail for that area.

Fuel Maps - shows your location and list of nearby stations sorted in cheapest order. Data is updated by users so we always update the price when buying fuel. The main feature we use is "my car" where we record fuel purchase and as we always fill to full it provides data such as economy, averages and more importantly total k's, fuel purchased and cost so far...ouch.

Wiki camps - check for reviews on camp sites and conditions, ie if closed. Shows points of interest so useful if not familiar withe area and need to see what is around. We have booked a couple of tours days in advance by reviewing feedback which also shows costs etc. The sites also have the link to their website along with phone numbers, photo's etc. You can select the database for the state you are in and download that before you go so not using data on the road as it does update when in mobile range. We just sync this when at free wifi area ie caravan parks.

Hope this helps

Mark