Kast - Because the player directs the progression

Valkyrien Skies, Create

Airships and automated systems to craft, modify and build indefinitely!

ComputerCraft (CC:Tweaked)

Small computers that can communicate and interact with the world.

Farmer's Delight

A nice little addition to the normal and boring default minecraft crops, with unique recipes compatible with Create.

Oh The Biomes You'll Go, The Twilight Forest, Blue Skies, IntoTheVoid, Unusual End, Amplified Nether

More unique biomes and dimensions (both vanilla and modded) with their own bosses !

Doggy Talents

Way better dogs with equipement and training!

SecurityCraft

Better security, reinforced blocks, almost unbreakable storage to secure your stuff from other players and even mobs.

MC's gun mod, Storage Drawers, Camera Mod, Simple Shops, Rotten Flesh To Leather Mod, Quark

Small utilities, rather easy to make that will improve a little (or a lot) the experience.

Also features the wild update!

Just Enough Items, Potion/Enchantement Descriptions, BetterF3, AppleSkins

GUI add-ons to show what minecraft don't bother showing normally, and almost removing the need of a quick internet search when searching for crafts and items

Jade, Neat

In-game GUI to know what you're looking at

Visual Workbench, Presence not Required, Damage Tilt

Small details that solves small issues

Seamless/Better Loading Screen

Better Minecraft loading screens when joining a world, a server or game startup

Also contains Distant Horizons, that allows you to see from far away

Canary, FerriteCore, Radon, Entity Culling, Smooth Boot, Smooth Chunk Save, Fast Workbench/Furnace, Pluto/Saturn

Optimize some of Minecraft's aspects that need it (entity render, memory usage, lighting engine, auto-save...)

AI improvements, Attribute fix

Fixes common problems with Minecraft mobs' AI and attributes