Hi Garry!
A height adjustable viewing chair will be a worthwhile investment.
Comfort at the telescope is important to get the most out of any viewing session.
To help you find stuff of interest, I recommend you download stellarium (free download) and a great program.
Also, when you are buying your DOB, try to ensure it has a Right Angled finder scope.
Add a red dot finder to help you quickly get it pointing in the right area of sky.
These are my 4 essentials.
Enjoy!