"Mekanism is an expansive, completely independent mod aimed at giving you a unified, high-tech experience while playing Minecraft, whether it be by itself or with other mods such as IndustrialCraft or BuildCraft. It features all the ore processing machinery you've come to love, as well as other advanced mechanics and items that will improve your world. Build yourself an Electrolytic Separator, give it water and energy, and you have yourself a constant oxygen and hydrogen supply. Output the hydrogen to a Hydrogen Generator via Pressurized Tubes to power a set of advanced Energy Cubes. Make yourself an Osmium Compressor and a Metallurgic Infuser to create advanced obsidian alloys."
"Mekanism uses a tier-based system when organizing several of its core features, including Energy Cubes and Factories. There are four tiers: basic, the simplest tier, advanced, the second-most basic tier, elite, the second-most complex tier, and ultimate, the most complex tier. You can upgrade tiers by placing the component in a crafting grid and surrounding it with the necessary resources for the next upgrade (I recommend NotEnoughItems!)".
"By the time you've been using Mekanism for a while, you'll have a near-instructible suit of Obsidian Armor, be obtaining four ingots for each ore you mine, have the ability to fly wherever you want with the hydrogen-powered jetpacks, and have a cute robotic friend following you around while you mine."
Above Italicized text from the Mekanism post on the Minecraft forums
Items
Energy Storage
- Basic Energy Cube
- Advanced Energy Cube
- Elite Energy Cube
- Ultimate Energy Cube
Generators
- Heat Generator
- Solar Generator
- Advanced Solar Generator
- Hydrogen Generator
- Bio-Generator
- Wind Turbine
Machine Components
- Solar Panel
- Atomic Core
- Control Circuit
- Steel Casing
- Enriched Alloy
- Enriched Iron
- Energy Tablet
- Electrolytic Core
Machines
Factories
- Basic Factory
- Advanced Factory
- Elite Factory
- Electrolytic Separator
- Enrichment Chamber
- Osmium Compressor
- Combiner
- Crusher
- Theoretical Elementizer
- Metallurgic Infuser
- Purification Chamber
- Energized Smelter
- Electric Pump
- Chargepad
Cables
- Universal Cable
- Mechanical Pipe
- Pressurized Tube
Ingots
- Obsidian Ingot
- Osmium Ingot
- Bronze Ingot
- Glowstone Ingot
- Steel Ingot
Armor
- Bronze Armor
- Glowstone Armor
- Lapis Lazuli Armor
- Obsidian Armor
- Osmium Armor
- Steel Armor
Tools
- Paxel
- Bronze Tools (Pickaxe, Shovel, etc.)
- Glowstone Tools (Pickaxe, Shovel, etc.)
- Lapis Lazuli Tools (Pickaxe, Shovel, etc.)
- Obsidian Tools (Pickaxe, Shovel, etc.)
- Steel Tools (Pickaxe, Shovel, etc.)
- Osmium Tools (Pickaxe, Shovel, etc.)
- Electric Bow
- Configurator
- Atomic Dissambler
Teleportation
- Teleportation Core
- Portable Teleporter
- Teleporter
Ore
- Osmium Ore
Upgrades
- Energy Upgrade
- Speed Upgrade
Blocks
- Osmium Block
- Coal Block
- Refined Obsidian
- Refined Glowstone
- Bronze Block
- Steel Block
Fuel
- Bio Fuel
Dynamic Tank Components
- Dynamic Tank
- Dynamic Glass
- Dynamic Valve
Tanks
- Gas Tank
- Storage Tank
Changing Time/Weather
- Steve's Stopwatch
- Weather Orb
Other
- Robit
- Compressed Carbon