You can do everything in this game in green lvl 80 gear. (masterwork gear)
I suggest you start with that first, it's really cheap (around 4s a piece and the stats are not that far behind exotic). Gear has little meaning unless you want to min/max. Once you buy your green 80 gear of whatever stats you want you can focus on exp dungeons, fractals (you can do fine in fractals without agony resist till around lvl 20sih), and you can focus on dynamic event chaining in Orr to get karma to buy exotic gear from the vendors.
But it really comes down to what do you want to do in the game? And you do it and you are rewarded for your current level (which is 80) so do whatever you feel like playing.
To add something, go see the major events, you know, dragons, wurm, golem etc. Get gear from there (usually it's stuff your level or close to it) or if it's not useful sell it and get gear you can use from auction house. You can also do dungeons and get the tokens for the gear from there.