You don't need everything on day one. This is the order we'd add things in.
Levels 1–10
Questie for quest givers and objectives on the map. With the Enhanced preset you already get objective areas; Questie adds givers and turn-ins.
Leatrix Plus for small fixes (auto-sell junk, faster loot).
Levels 10–20
- Talents start at 10. Nothing to install; read your class's leveling guide.
Bartender4 or Dominos once your bars fill up.
Levels 13–30: first dungeons
Deadly Boss Mods (DBM) or 
BigWigs Bossmods before Hall of Thanes (13–18) or Ruins of Lordaeron (15–20).- Details! Damage Meter for the death log.
Levels 30–60
Pawn to compare quest rewards quickly.- A bag add-on:
Baganator or 
Bagnon. 
TomTom for coordinates from guides.
Quest-helper options compared: Questie and the alternatives.