First before I even set foot in the thing I'd check that there aren't any F-ed up experiment that's going to happen, here's my list:
1. A place to grow loads of food and also some trees that will make oxygen and Water purifier so I don't start getting irradiated
2. between 400-500 people who I can trust along with people who are scientists armed security and engineers, so the vault survives
3. A status chamber that will keep my body and mind alive for decades, my plan is to be the Overseer and after a the first few years I will go into the status chamber for a decade or 2. So I can survive to see the world in a few centuries, it would also have loads of defences so no one tries to kill me. I will also stay out of the Chamber for Five years, then go back in until we leave the vault
4. Journals, Books, tons of writing equipment, I need at least 2000 pens with clicky tops and games (board and video) so I don't get bored
5. A good source of electricity, then the vault should make its own renewable source
6. loads of space inside the vault, so everyone has enough room for everything and we still have some to use
7. A terminal that connects to a satellite to show updates about the area around the vault, it would work like google earth except much much better and sophisticated
8. A computer with all the information and software to make a game and also have loads of space
9. A database containing all of earth known history
10. Guns for the security guards, like 10mm pistols. I would have more powerful weapons and some ammo for them. I would also have some Power Armour
11. Animals, for meat and companionship
Thats all I can think of, if everything works out we should be repopulating the earth in a few centuries and I will be there to see it