Hi Wayne,
I had a 5" ETX as my main scope for years and there is heaps of Deep Sky stuff you can see, if you know what to look for, are realistic about what you will see, and take the time to train your eyes. Darker skies will help but many are visible from suburbia.
Main things to look at with this size scope would be globular clusters, and compact open star clusters. Hundreds of them.
Some of the brighter nebula are visible, like the Tarantula, Orion, Lagoon and Eta Carina. Don't bother with nebula filters with this size scope.
Some of the brighter planetary nebula, like the Saturn, Ring, Bug and the blue one in Centaurus are visible.
A few of the brighter galaxies are worth looking at too like NGC 1365, NGC 253, NCG 55, M83, M104, and Centaurus A. The Magellenic Clouds have many objects in them that you search through.
The views obviously won't be the same as a larger aperture scope but it is amazing what you
can see with this size scope.
For more info try to get some viewing guides for smaller scopes. A constellation guide for small scopes can be found at:
http://www.weasner.com/etx/ref_guides/toc.html
A really great book is "Turn Left at Orion: A Hundred Night Sky Objects to See in a Small Telescope - and How to Find Them"
There is another guide that keeps getting published in various guises such as "Sky Watching". Have a look in your local Australian Geographic store.
The Sky and Telescope Pocket Sky Atlas is an excellent star chart for this size scope.
Have fun!
