Only three things you gotta know:
- computer mods rule
- magic wands drool
- don't dig straight down
You can buid a gigantic chest that holds hundreds of thousands of blocks of cobblestone, perfect for those builds where you want something fancier than dirt but not as fancy as smooth stone
(Pack image listed on google as good for reuse with modification)
Included as all-around tech mods: Mekanism and Thermal Expansion
Various high end power generation mods, compatible with RF and Joules allow for crazy builds
CC:Tweaked, OpenComputers including support for Python the number 1 programming language, and Integrated Dynamics help monitor and control machines
You can traverse an abandoned lost city and build up a settlement with MineColonies, rebuilding society and overcoming roguelike dungeons one block at a time
Mods have extensive expansion from the base:
Thermal includes RFTools and it's children, Redstone Arsenal+Flux
Tinkers includes armor and leveling systems
Every release gets fewer and fewer duplicate items: for example, there used to be two diamond gears with varying resource requirements, now there's just one.