Magic World 2 does indeed seem very interesting for me, especially with the Jadecat Mixpack Texture pack. But Hexxit, even though its a little outdated, has some mods that apparently make exploring more interesting, adding a lot of dungeon types, besides adding magic and weapon mods.
And you recommend Horizons, not Tech World 2, or Tekkit, for tech stuff?
And I see that a lot of you recommend Test Pack Please Ignore. But it says in the title to ignore it. Who am I to disagree?
Also, about ATLauncher... at first look, it seems that most of its mod packs focus on hardcore survival, not very appealing to me. The FTB and Tekkit Packs seem the most diverse and interesting, not being focused on masochism.