Well that is an extremely open ended question. We do I start?????

These are among the most drought tolerant plants that I know about. Should give a good variety to work with.

Eremophila maculata
Correa glabra
Banksia praemorsa
Dryandra nivea
Dryandra nobilis
Banksia lemmaniana
Correa reflexa
Goodenia ovata
Dampiera purpurea
Wahlenbergia communis
Myoporum viscosum
Myoporum insulare
Olearia ramulosa
Indigofera australis

It would help us a lot, dee, if you would tell us where you are. As greg implies, the list of drought-hardy plants is SO huge. "Drought hardy" doesn't mean the same thing in Sydney, for instance, as it does in Birdsville. The list would be narrowed down a bit if we had some idea of the climate and soil your audience is dealing with, and what sorts of suppliers you have in your particular bit of Australia.
I, for instance, (being in Toowoomba)like to see people planting dry rainforest species. They are as tough as nails, and have quite a different look from the plants on Greg's list - but there's no point in my doing this if they're not the kind of thing people would grow wherever it is you live.
Trish

I never water my Grevillea banksii red or white , Grevillea pteridifolia, most I have grown from seed, or any of my Callistemons they have only got what water has come from the sky same goes for Hymenosporum flavum, Backhousia citidora, Backhousia myrtifolia, Melastoma affine.

These grow very well here South of Brisbane seeing we have had drought conditions for the past six years and not permitted to water with a hose only a bucket so they have missed out, having said that they are now flying away even more due to the rain we have has this wet season.. There are more though they are getting into the bigger trees size. You did not say if you wanted creepers, shrubs, or trees..

I don't know if that is what you are after though it may help.

You should be telling them to use indigenous plants whereever possible. They are obviously the most drought-proof plants you can get (as long as they are planted in similar microclimates to where they grow naturally).

You're quite right, Pos02. I sometimes get quite exasperated at the attitude that any Australian plant is a "native". I am very jealous of mistymorn's rainfall levels, that he/she can regard Melastoma affine, which is a rainforest plant (and a lovely one), as "drought hardy". There's no way we could grow it here in Toowoomba without supplementary watering - yet we're hardly in what you'd call a "dry" part of Australia.
Another important factor in choosing plants for success in drought is what time of year you have your dry spell. Some very drought-hardy south-western Australian plants don't cope at all well with Eastern Australia's wet summer/dry winter climate, becoming very short-lived plants if they succeed at all.
My favourite drought-hardy shrubs include:
Alectryon diversifolium
Maytenus bilocularis
Pittosporum angustifolium
Petalostigma pubescens
Psychotria daphnoides
Erythroxyoum australe
Croton insularis
Senna artemisioides
The last is the only one with showy flowers. It's also the only short-lived one. The others all have either attractive fruits or red leaves.
As mistymorn says, there are lots of drought-hardy and attractive trees, of course. Here are a few, not too big, with nice dense, green canopies.
Flindersia collina (lovely bark)
Flindersia maculata (more drought hardy still)
Allocasuarina torulosa (lovely, but very different bark)
Brachychiton populneus
Brachychiton rupestre
Atalaya hemiglauca
Geijera salicifolia
Another clue, dee, is to look around at what natives your council is using as street trees. You can be sure they are tough.
Trish