Technic Launcher

The Technic Launcher is a whole new launcher for Minecraft, put together by the Tekkit team. It includes various modpacks that add tons of great gameplay changing mods.

Tekkit - Adds BuildCraft, IndustrialCraft, and Forestry among various other mods that focus on total world automation via machinery. Set up a factory that pipes oil to a quarry, pipes the quarry's loot to an automatic crafting table, manufactures stone picks, then distributes stone picks to bases all over your world through long pipelines. Or for those of you eco-friendly peeps, set up massive tree, pumpkin, wheat, and watermelon farms that harvest, plant, and tend to themselves. Can be played in SSP and SMP.
http://thetekkit.wikia.com/wiki/The_Tekkit_Wiki

Technic - Essentially an SSP-only version of Tekkit, however it adds plenty of mods that focus on exploration and combat. Such as Millenaire, an entirely new village system that creates villages of four varying races that you can trade with, join, and help develop--or destroy! Like to go solo? Go ahead and find a pirate ship or tower and take it over to be your own base. Enjoy hacking your way through massive dungeons? Make your base out of an underground labyrinth or seed-built CARuins. Or if you want, use the next mod...
http://technicpack.wikia.com/wiki/Technic_Pack_Wiki

Hack/Mine - Pronounced "Hack Slash Mine," this is a mod pack that focuses heavily on weaponry and intense combat situations. Raid dungeons, towers, and go on other kick-ass adventures. But before that, make sure to choose your class. Yep! Choose to be either a warrior, ranger, or mage. These classes each have weaponry, army, and stats that benefit them more than other classes. Stats I say? Stats I say! Level up your strength, dexterity, and other skills to become the best fighter known to Minecraftia. Available in SSP and SMP.
http://hackslashmine.wikia.com/wiki/Hack_Slash_Mine_Wiki

Yogbox - Not into The combat of Hack/Mine? Nor the heavy machinery of Technic or Tekkit? Want more of an adventure element, essentially a much greater expanded version of vanilla? The Yogbox is for you! It adds a lot of new mobs to tame and kill, new structures to overtake or explore, new ores to mine and craft with, and a fuckton of other features great for SSP.
http://yogbox.wikia.com/wiki/Yogbox_Wiki

VoxelModPack - If you want a less buggy Minecraft with a more enjoyable playing experience, get this. The VoxelModPack adds no new content or features, rather fixes a gargantuan size of bugs and makes things run smoother.
http://www.voxelwiki.com/minecraft/Main_Page

Vanilla - Sick of all these ogres breaking into your house? Get killed by the necromancer too many times? Can't conquer that tower? You're free any time to switch back to vanilla Minecraft, also accessible from the Technic Launcher.
http://www.minecraftwiki.net/wiki/Minecraft_Wiki

So what are you waiting for??? Get this NOW.

Holy shit

I gotta tell you guys about my world so far. Using Yogbox:

>Spawn in a flat area, seems really nice.
>Build a house in the side of a hill.
>Make a small farm.
>Notice tower far off in the distance.
>Sail across a sea, reach land opposite of mine.
>Tower in the ocean about two hundred blocks off the coast of the new land.
>Village and mob castle on peninsula.
>A hundred blocks away is a skeleton siege town (A skeleton siege castle/town is a large wall with a few buildings inside of it. A siege castle features more militaristic buildings inside of it, a town has more civilian buildings in it).
>Break into the town by digging under the wall.
>Kill a couple skeletons nearby, take over their church.
>Keep in mind this is a literal siege now. I'm inside a walled structure, fighting off skeletons from inside of their church.
>Make a quick run back to my old base, gather supplies for the battle.
>Kill a ton of skeletons.
>Go into the main tower, home to a necromancer (the main boss of the Better Dungeons mod).
>Kill necromancer, obtain four diamonds.
>Loot the entire town.
>Lots of supplies and weaponry.
>Decide to make the siege town my home.
>Sail back to previous house, move everything back to the new place.
>I now have an awesome base of operations right next to a Millenaire village.
>Look at the day counter in the top left corner.
>Day 7.
>In a week I built a home, farm, sailed to a new land, conquered a castle of the undead, then renovated it into a hub of supplies (aka it has a farm, tower home to my bedroom and storage room, armory, church, and food house).
>Jump onto a nearby tree using cloud boots that give me higher and farther jumps.
>See a palace in the distance. It's made of sandstone and has blue roofs.
>Also full of skeletons and a necromancer.
>Kill all of them, acquire seventeen diamonds, hookshot, records, etc.
>Take over the mob castle next to the Millenaire village, get even more loot.
>Over the next in-game week I conquer a mob tower, tree dungeon, another mob castle, and another sandstone palace.
>I have full diamond armor and tools, with another twenty spare diamonds in my chest.
>I also tamed a horse for quick travel and built him a pasture just outside the walls of my town. My weapons and armor have amazing enchantments and I have a score of over 8000.
>I'm invincible and it's only day nineteen.

Here's a pic of me for you all to be jelly at.