Hi Matt,
I observed hundreds of open clusters, most of the globular clusters, scores or planetary nebula (with an LPR filter), and over 1000 galaxies with my 8" before I bought a 14.5".
As you live in the Mornington Peninsula, why not just join the Mornington Peninsula Astronomical Society (cost $50 pa)? Then go to a member's viewing night at the Briars and have a look through telescopes. The Society owns a few telescopes, including an 8" one from memory, and members have quite an assortment of smaller and bigger ones.
After that experience, you'll have a pretty good idea of what you want.
Check out their site at
http://www.mpas.asn.au/
Alternatively, I'm pretty sure that you can come along for one complimentary visit if you ask beforehand.
Regards,
Renato