Hi Greg,
Some good advice already!
You have a telescope that will give you some amazing views, and as you progress in the hobby it should keep you happy for a long time.
Wrt to eyepieces, you have a 26mm which will give you around 64x with your scope, with a field of view of a bit over 1 degree: about 2 x the width of the moon. This will give good views of most of the Messier objects; but don't expect many of them to be very bright from the suburbs! Your 6.5mm eyepiece will give around 256x with a field of view of around 14 arc-minutes (about 1/2 the width of the moon). This will give you great views of the moon, and good views of the planets on nights with steady "seeing". You will need to let your telescope reach ambient temperature (usually an hour or two if you bring it from inside the house) to make the most of this high-power eyepiece because heat from the cooling mirror will affect the view, so don't expect the views to be sharp straight away.
I would suggest that down the track you might like to get an eyepiece that will give you around 100x: around 15 or 16mm.
I would also recommend strongly that you get involved with the Astronomical Society of SA, as there are many people who can help you, and you can get involved in members' viewing nights, meetings, camps etc. which will help you enormously. See:
https://www.assa.org.au We have a library which is open at the meeting nights as well, and heaps of resources that can be borrowed by members for free.
We have monthly meetings at 8pm on the first Weds of each month at the Adelaide Uni, and there is a "beginners" lecture at 7pm on each of these nights. These are open to anyone (you don't have to be a member), and I think you would find them very beneficial.
As a life member and ex-President of the ASSA I am happy to talk about possibilities with you: feel free to send me a PM and I will give you my contact details.
- and check out some of the magazines that are out there, such as
Sky&Telescope, and
Astronomy
All the best, and enjoy your new scope and hobby!
- Dean