SBR, 2,000rnds of ammo, bear-proof body armor.
Ha. 'Nough wiseguyin'.
I haven't been in a while, but what you "need" may change with how you're getting to your site. Driving in? Backpacking? Bike? Raft or Canoe?
Just off the top of my head:
A "sleep system." Whether you hammock, cot, or lay on a pad, make sure they're roomy, warm & comfy enough for you to get a good night's sleep. Test your system out at home if you can! Sleep on the floor or in the yard and work it out before you go.
A way to keep dry -- tent, camper, tarp, etc.
A good, reliable camp stove & plenty of the right fuel--no fun goin' hungry!
Knife, other utensils suited to your type of camping.
1st aid kit.
A way to keep bugs separate from you--spray/lotion, screening on your tent/camper/sleep area.
Comfy, versatile clothes & shoes--forget fashion, wear what works. Consider 'technical' wear that wicks sweat away and dries quickly
Water purification device.
There are hundreds of other things! No doubt you'll get quite a list from here. Have fun!
EDIT: And, of course, TP!