An Obsidian Plate - Obsidian pressure plate, only triggered by players
Applied Energistics - ME Storage, Drives, Crafting. Creates a large network of stored items for easy access
Atomic Science - Power Reactors (Nuclear, fission, etc.), anti-matter, strange matter.
Backpacks - Self explanatory
Balkon's WeaponMod - Muskets, Spears, Hatchets, Cannons, Dynamite, Blunderbuss, Warhammer
s
Big Reactors - Adds another power source, basically big fuck-off reactors. Main power source most likely
Buildcraft - Making machines to move shit around
Buildcraft: Additional Pipes - More pipes for moving shit around
Buildcraft: Logistics Pipes - iPipes
Carpenter's Blocks - Shit ton of cool new slanted blocks for detailing builds
ChickenChunks - Lets you load chunks if you aren't near your base/area (Chunk Loaders, Spot Loaders)
ComputerCraft - Computers, monitors, turtles (robots), modems, look more into it, it's cool. Let's you code
Custom LAN Ports - Makes LAN servers more like regular servers, probably not going to be used
Dimensional Anchors - Adds another chunk loader block
Dimensional Doors - Pocket dimensions, manipulate reality, form rifts, link dimensions, loot.
Ender Storage - Color coded ender chests, A.K.A. more storage (and ender pouches that link to them)
Equivalent Exchange 3 - Alchemy and shit, exchanging items for other items
Extra Cells - Addon for A.E., let's you store fluid in your ME system, fluid transport
Extra Utilities - http://wiki.technicpack.net/Extra_Utilities (Transport, building, crafting, a lot of cool shit)
Galacticraft - SPACE RACE SPACE RACE SPACE RACE SPACE RACE SPACE RACE SPACE RACE
Greg's Lighting - Floodlight, illuminated the floor under it so no need for torches, glowstone etc.
Immibis Microblocks - Pixel sized blocks for decoration and detailing
Inventory Tweaks - Self Explanatory, adds a bunch of inventory management tweaks
Iron Chests - Chests but with more storage
MineFactory Reloaded - Helps a lot with manual labour, like plant/animal farming, etc.
Modular Force Field System (MFFS) - Force fields.
Modular Powersuits (MPS) - Literal. Power. Armour. Really cool, mostly end-game shit.
MPS Addons - Addons for MPS, adds some new abilities to the suits.
Mystcraft - Let's you write books that create universes that you can travel to
Nether Ores - Adds Overworld ores to the nether
Not Enough Items (NEI) - Inventory tweaks, let's you see crafting recipies, etc.
REALLY USEFUL
NEI Plugins - Tweaks to NEI
Numina - No Info found, sorry
OmniTools - Adds omniwrench, replacing other mods tools into a single, ultimate tool.
OpenCCSensors - Computer craft sensors for sensing players, mobs, other entities, etc.
OpenMods - No info found, sorry
OpenPeripheral - (Can't explain it so here:
http://wiki.technicpack.net/OpenPeripheral )
ProjectBench - Upgraded crafting table
qCraft - Simulate quantum physics in Minecraft
Rei's Minimap - Adds a minimap on your screen that let's you add waypoints and stuff
REALLY USEFUL
Redstone Arsenal - Adds tools infused with redstone flux (Power)
Redstone in Motion - No Info found, sorry
Simple Power Storage - Adds a storage block called the Makeshift Battery that has two tiers to it
Simply Jetpacks - Self Explanatory, adds jetpacks to the game
Steve's Carts - A lot of new minecarts and minecart tracks for transport
Thermal Expansion - ore processing, power production/transport, liquid support, etc. (Mostly steam power)
Trade Booth - Player trading 24/7, offline and online, imagine the GE from Runescape
Treecapitator - Breaking one block of a tree makes the whole tree fall, you lazy fucks
Universal Electricity - No Info found, sorry
Vending - Adds a new block that let's you sell items for other items, useful in shops and shit
Waila - Describes what block you're looking at
WR-CBE - Wireless Redstone