If you are looking for a mod pack that pretty much has it all you need to check out the Feed The Beast Mod (also known as FTB).
Feed the Beast started as a custom challenge map in Minecraft. This map made used multiple tech mods. Originally it worked to allow a gamer to start in a void world with a small platform. The player then had to overcome a set of challenges.
It became super popular and expanded into a ton of other packs which then turned into the Feed the Beast launcher in November 2012 which was live-streamed to over 9000 people. Now FTB Modpack includes 30 amazing Minecraft mods that combined make for awesome game play.
These 30 mods combined ad an huge amount of content to the game. Things such as different realms that have different monsters and different bosses, energy systems, more ores, added armor, different biomes, etc. The best part is they all work together nicely.
Following is a few of the more well known mods that Feed The Beast Includes:
Buildcraft Mod which automates building, mining and crafting and also automates item sorting and pipe transport.
Railcraft ads steam boilers, more engines, liquid tanks and more rail stuff.
IndustrialCraft 2 which adds its own energy system to power its own machine blocks. This helps you get ores and turn them into two to three times the amount of ingots that you normally get in vanilla.
ComputerCraft Mod which allows you to protect your house with a password among other features.
Mystcraft Mod allows you to teleport. Basically allows you to time travel. This is called linking books. With linking books, you can teleport to different ages
Twilight Forest which includes new creatures, monsters and bosses that makes it magical.
There are a ton more awesome mods included within this pack so we suggest downloading it and check it out yourself.
Watch the Feed The Beast Video