[Comedian]

If you're looking for what books would be handy, I'd recommend High-Tech and Ultra-Tech, with either Gun-Fu or the soon-to-be released Tactical Shooting (depending on how realistic or cinematic you want). Both High-Tech and Ultra-Tech include equipment lists for stuff that exists in the Fallout universe as well as some new optional rules. Gun-Fu (and Tactical Shooting as I understand it) are mostly new character options and more optional rules to add certain flavors to the game. If you're new, you might want to hold off on the new books (or at least the additional rules added by the new books) until you can get the basic stuff under your belt.
My general advice to you as a new GURPS gm is:
1.) Walk your players through the character creation process if at all possible. If not, use pregens (GURPS Character Assistant makes character creation go faster if you're interested). Either way you are intimately familiar with what each character has, what they're capable of, and whether or not they are a good fit for the campaign you're setting up. Don't give them the book and expect them to come back with something that will work. It happened in my group once with 3rd edition, and I had to fight to get them to play a one-off in 4th several years later.
2.) Read the all the relevant sections of the Campaigns book until you can feel confident explaining the mechanics to your players without having to constantly refer to the books. Print out the charts that you know you will have to use (the speed/range table, rapid fire chart etc.)
3.) Run a couple of one-off combat-centric scenarios with pre-gens with your players to help all you get a feel for the rules. Use the rules you feel comfortable with and then integrate more as you get more proficient with the rules. Side benefit is you get to test the system on your players before you do the leg work involved in building a campaign.

Anyway, hope that helps. Good luck with you're campaign!