Mods without version numbers are not yet available (but are expected to be available Soon (tm) and will be included for sure when they are).
Note: Current version #s reflect the next server update, not the current ones.
Minecraft Forge is what loads all the mods and lets them all work together.
Project HomepageShows mob info when mousing over it, along with damage numbers when you hit something (client side only mod.)
Minecraft Forum PostExtra in game info (shows game time, biome, etc.) Client side mod.
Minecraft Forum PostA few handy inventory/chest related tweaks. Client side mod.
Minecraft Forum PostCrafting/Smelting/Etc recipe in game guide/lookup.
Minecraft Forum PostClient side mod that will show what mod an item is from.
Project HomepageAdds a whole bunch of new biomes to the game (even in the Nether) along with new decorative blocks and flowers.
Minecraft Forum PostTo the moon and BEYOND!
Project HomepageAdds real villages that build up over time, raid each other, etc. Players can help and trade with these villages. May need to tweak the rarity.
Project HomepageAdds multi-leveled dungeons to the game. Would need to tweak the config to make them more rare.
Minecraft Forum PostAdds various structures (ruins and such) to the overworld. Again, config would need to be tweaked to make them much more rare than the default settings.
Minecraft Forum PostAdds a new dimension containing a lot of new items, blocks, and bosses to fight.
Minecraft Forum PostAdds new types of rocks in the ground. Need to test with biomes 'o plenty, etc.
Minecraft Forum PostThaumcraft addon that adds magitech that bridges Thaumcraft with IC2.
Minecraft Forum PostA magic mod all about natural magic (potion brewing, dreamweavers, circle magic, etc.)
Project HomepageAdds a whole new type of storage system to Minecraft.
Mod homepageThe classic tech mod. Need to look into various addon mods such as logistics pipes.
Project HomepageProgrammable computers (using Lua), touch screen monitors, turtles (programable robots), and more. Look into various addon mods such as extra peripherals.
Project HomepageFarming and forestry related things. Look into various addon mods such as extra bees and magic bees.
Project HomepageThe other classic tech mod. Look into various addon mods such as Advanced Machines, Compact Solars, Compact Windmills, etc.
1.7.2 Builds PagePortal guns.
Project HomepageYet another tech mod based on thermal expansion stuff.
Project HomepageLots of useful misc stuff.
Project HomepageReplacement for most of redpower (wires, redstone circuits, tubes, and lighting.)
Project HomepageYet another tech mod.
Project HomepageNew way to smelt ores, make allows, and tools and weapons.
Minecraft Forum PostBookcases, shelves, armor stands, tables, chairs, printing presses, etc.
Minecraft Forum PostAdds desert plants and allows for using cactus as tools.
Minecraft Forum PostMore types of buttons and levers and stuff.
Minecraft Forum PostAs the mod itself says, "A bunch of fairly useful things."
Minecraft Forum PostNew kind of flower pots (also useful for growing crops).
Minecraft Forum PostAdds things like one way glass, hidden doors, pressure plates, levers and more.
Minecraft Forum PostFormerly Middleage mod. Adds statues, flags, and other decorative blocks.
Minecraft Forum Post