After the Main Storyline...
After the Main Storyline there are things that needs to be done.
Leveling gathering for mats needed for Crafts.
Crafting things and leveling crafting.
Making a Fortune selling the Stuff you get from gathering such as Shards and HQ Materials.
Leveling the other classes to level 50 to unlock all class/Job storyline cutscenes and cross-skills.
Darklight set for Endgame by farming CM and TP for their 100 tomes per completion
Getting Your first Relic while becoming poor in the process. :p
Endgame such as Hard Mode Primal.
So what are you all doing now that you're done with the Main Storyline?