Things you may purchase :

1 - dewshield, we dont want ending the session earlier by dew!
2 - A Red dot finder! something like EZ-finder or other one you may like to find the star for aligment!
3 - Power connector so you can use it at home with your normal power outlet!
4- Powertank or jump start battery so when you go out you have plenty for using it some nights in a row.
5- A pelican brief or meade's etx-80 box so you can store your scope with the accesories (you dont need this if you buy the back pack version)
6- Moon filter when using the scope with full moon.
7 - Solar filter! hey you can use it in daylight too to watch the sun with the proper solar filter! (around 40 to 60 bucks)
8- A 2X barlow..to double your eyepice power, the etx-80 have one already internally but i have find not very good reviews about it, its useful has far i know but its not the best.
9 - Eyepices, whatever you may like stand alone eyepices or maybe a zoom eyepice so you can cover more ground (and less accesroies around), the etx-80 already comes with a 26mm (very useful) and a 9mm eyepices (its ok..but small pinhole to see). I would prefer use a zoom eyepice even that its a bite expensive than a normal eyepice bt you will cover more mm (like 24mm to 8mm zoom eyepice)...there are many around to chooose..but many favors the baader zoom eyepice (orion have a couple good, WO and others).