What you need to bring for camping:
Bring a cooler with favorite drinks.
Have sandwiches and snacks for all days
Bring camping chairs if you feel like it -
Bring a camping table if you want
Wear comfortable clothing
Definitely bring camera and video
You might need a tent (don't spend more than $60) - I always sleep under the stars as long as it does not rain.
You will need a saleeping bag (don't spend more than $60 unless you plan on snow camping sometime soon),
You will need a sleeping pad (foam or inflatible) - Get a wide one rather than a narrow one.
Unless you are used to sleeping on a cot - I do not recommend them
A sleeping bag with a pad underneath is much more comfortable and leaves you more room to move.
Best map : AAA Death Valley
GPS? not really needed, but they are fun to have
Phone? Your cell phone does not work out there
Books? Buy them after the trip. If you insist on reading up on DV before the trip: The Explorer's guide to Death Valley is pretty good, ISBN0-87081-409-5