Most people will do a Masters degree instead of or part of the 2 years work experience and they will get the title Professor or as already stated a PhD gets the title of Dr.
If you do your course at Monash you could have BPsych(Hons) Monash after your name.
You can get another nifty title by joining the Australian Psychological Society http://www.psychology.org.au/membership/applying/grades/. Then you can also have MAPS/Assoc Maps/FAPS or Hon FAPS after your name depending on the type of member you are.
A Psychologist with a Masters degree would have the title you and I would use (i.e. Mr for Males, Mrs/Miss/Ms for females). You would be able to stick titles after your name though, so say if I've finished my Masters in Psychology and registered to practice, my title might be say.
Mr Glock Meister BBNSc (Hons) MPsych (Clinical Psychology) MAPS.
And that's the title you'd stick on your business cards say. If say I have a Doctorate, then I could use a title Dr.
Dr Glock Meister BBNSc (Hons) PhD MAPS
Professorships/Associate Professorships are associated with university appointments. You are NOT entitle to use that after graduating with a Masters.
Another note is that you don't have to be a member of the Australian Psychological Society to practice as a Psychologist (I'm not a member of the APS, even though I'm eligible for membership)
A PhD is just a postgraduate degree that's 3 years (Masters is 2). Honours is actually similar to a PhD because you'll be helping someone else with their research and you still have to write up a thesis only you'll be doing your own research if you do a PhD. Also when you graduate with a PhD you get a fancy blurb talking about your ~groundbreaking research.
A PsyD is more hands-on and less research/theory based than a PhD (I think).
Basically from what I understand, most PhD programmes lead to research careers in Psychology whereas DPsych has more of a clinical focus. The DPsych (and the MPsych) have clinical placements within the course which cover the two years of psychological practice that's needed to be admitted as a full Psychologist.
The only note is that the research you do as a PhD/DPsych/MPsych candidate is hardly going to be ground-breaking. It will be however, a unique addition to the scientific body of knowledge that we have in terms of Psychology.