There is collecting codex and datacron for you (although I bet there will be an FAQ for collection all datacrons within 1-2 month of game release).
Codex are lore objects you can interact and you can read the story more in your quest log.. They are kind of like "books" in WoW.. There used to be a lot of them back in Vanilla/TBC.. but I guess Blizzard eventually find no one reads them
Datacrons are objects that are usually hidden in places that are very hard to reach.. They give you PERMANENT stats bonus (usually for presence.. which is a stat that boost your companion's stats).
As for reps.. There are light side/dark side points for your grinding pleasure.. Getting them will unlock titles.. There are tons of titles in beta already and I am sure there will be more in the release.
Oh.. and you can also grind for companion's affection points as well, it will unlock item upgrades for them and new quests.