Need help, gearing a lv80
Best starter gear would depend on your general playstyle. Something safe to go with is either berserkers (pow/prec/critical damage) or knights (pow/prec/tough) or even a mix of the two. Use level 80 rare armor for now until you know what you want (browse official or unofficial forums for builds to give you inspiration), then get the exotic versions (berserker from CoF/CoE dungeons for example). Your old level 80 rare armor can be salvaged using master/mystic salvage kits in attempt to get ectos.
You are probably safe with using berserker trinkets regardless of build, so if you have the laurels, get an ascended berserker amulet (either offensive or utility depending on if you plan to frequent fractals a lot).
As for tanking, the game generally isn’t designed to allow excessive tanking. Work on your playstyle by adding more dodge rolls in.