Ironically, I think it's the branch of the timeline that a lot of Zelda fans disagree with, the Downfall timeline.
The Downfall timeline has the first four released Zelda games in which these Zelda staples that make a Zelda title "Zelda-ish" were first established. Everything from Link to Zelda to Ganon to Hyrule to the Master Sword to the Triforce to dungeons to fairies to bombs and bows and boomerangs- All originated in this timeline.
Not to mention, the good old Zelda formula that most of the titles follow originated here in ALttP. So to me, the Downfall timeline is the most "Zelda-ish".
Also, why is this thread in the Zelda Wii U forum...?