I'd have a designer come in and come up with a design. As you've stated, 'With a blank canvas..'

Definitely use as many native and indigenous plants as you can.

Lilli Pilli's are great a first choice for hedging either formal or informal.

Before you choose any plants get your soil type checked. Then do that research on what grows in your area, checking what will cope with your climate - rainfall, heat, how much sunlight on the garden etc. agree with Timandra: trees so important, and as they take the most time to grow, get them in first as your structural elements, and work the garden around them, and ask yourself about where their shade can be best employed. Good luck - and enjoy the process, creating a garden is immensely satisfying!

Pinterest has top 12 dry bed gardens, they are stunning and you'd gain ideas I am sure but I would check your area where you live to see what thrives then decide what to plant based on that also besides any designer than can help a really good nursery has staff that know what they are talking about may be of help to you, good luck.

It is a good idea to find out what natives are local to your area as this will provide the local birds and bugs with the food that they need. Your home site was probably cleared of native vegetation to make way for your home, so it is good to give back some habitat. I know that you want a dry creek bed, but also think of providing some water for your birds too. When designing a garden from scratch, think of breaking the space into 'rooms' that you link with paths using larger shrubs to hide the view into the next room to give wandering along the path a bit of a sense of mystery and discovery.

Think of taller plants such as gums, wattles (which are usually quick growing but short lived) and banksias, then have mid layer shrubs and bushes like taller grevilleas and correas, then ground covers like prostrate banksias, hardenbergias, creeping grevilleas, etc.

For your info:

http://www.plantthis.com.au/plant-selector.asp

We have some amazing garden bridges available on our website.

http://happychappyoutdoors.com/garden-bridges/wooden-garden-bridge-2400-600-handrails

thanks for all your advice. our soil is mostly clay with sand. the nursery told us to dig deep holes and put fresh loam, gypsum and compost which we have done for every hole and tree. We planted 26 natives along the fences mostly grevilleas, callistemons, lily pilys, and woolly bushes and a couple of fruit trees. Everything we plant we have had to fence off otherwise my dog digs it up. She is getting better at not doing this but still does now and then and gets told off. she has mounds of dirt up the back to dig in. We have also put in lots of lawn and a couple of big native gardens which are looking great now. however in saying this now we are having a very dry winter and not alot of rain so having to water everything gets expensive. We are about to finish off my garden area with rocks for river bed and cottage mulch for around the plants etc. will post a photo when finished.

This is the final phot completed yesterday