Terrafirmacraft.
I've been playing minecraft a long time, and frankly... It's too basic, too easy, and really takes away the survival aspect of the game it once had when I first was playing it.
I found a mod through some searching that makes it a lot more realistic so to speak. I'm not going to say too much here, but rather I'm going to post a video explaining it, but I'll get the highlights.
This mod aims to make a more realistic world (as realistic as can be achieved in minecraft). It adds countless new types of everything really. You know that basic system of having 5 different types of tools? (Wood, Stone, Gold, Iron, Diamond). Take that, and add several dozen more types of ore that the basic tools can be made with.
The world is made up of many different types of stone, dirt, trees and everything else to make it more real. Things function differently too... Oh, how they function differently. No longer are the days of simple crafting, and I can't explain this without great detail, I'll let the video do that, but what you get from trees for example is not just 5 pieces of wood that can quickly make planks. You get logs: Logs which you can do a lot with. A lot of the stuff you do involves using a fire pit, anvil, or other machines to get what you need. You now get sticks from leaves which you have to throw to the ground and light on fire to make a fire pit, and this fire pit needs logs to fuel it, different logs heat differently, and there is just so much to do. You can also have cave-ins happen now. I'm barely scratching the surface here too.
This mod, is really something to literally make the game an extensive survival game.
Check out a mod spotlight. It's 48 minutes long, because that's how long it takes to cover most of the stuff you can do:
Mod Spotlight - TerraFirmaCraft - Part 1 - YouTube
Link to mod's page:
[1.4.2]TerraFirmaCraft - Survival mode as it should've been. - Minecraft Forum