Necessities on any given camping trip:
 * Tent (with rain fly AND ground cloth)
 * Backpack (to pack in/out)
 * Sleeping bag and ground pad (thermarest, etc.)
 * Water vessels (2L minimum is wise)
 * TP!
 * Warm clothes, at least one pair, no matter the season
 * Socks, multiple pairs
 * Gloves (in fall/winter/early spring)
 * Boots/well-sealed shoes
 * Food you absolutely want to eat 
 * Cooking gear to cook your food with (pot, spoon)
 * A sponge and bio-friendly soap to clean with (Dr. Bronner's is great)
 * Flashlight/Light source e.g.:
  * headlamp          
  * maglite, mini maglite, cygolite headlight
 * Knife
 * matches or other source of fire
 * camp shoes (e.g., water socks or sandals)
Suggestions for increased relaxation/fun/non-suckage:
 * Folding chairs
 * Air mattress
 * cards/travel games/books 
 * stove/cooktop
  * propane screw-ons are nice but can be heavy
  * alcohol stoves are light but small, take longer to cook things
 * DEET