Bronze, your list of essentials will very much depend on how long you are going for and what sort of camper you are.
The Glampers need solar powered fairy lights
The Utilitarians need plastic boxes with lids
The Minimalists need a spoon
The Outwell family need matching sleeping bags and fruit bowls
So your list is fine, but in a cosmo type analaysis I sense you are a minimalist at heart .
I second MisSal re self inflating mats but we have Thermarests which are an altogether better and classier type of self inflating mat
Cooking stuff, chopping boards, knifes, few pots and pans, can opener.
Box (see I am a utilitarian) with spare pegs, duck tape, first aid kit, mossie cream, tenacious tape etc
Plastic backed picnic blanket
Chairs? Table?
Torches, lantern, head torch
Lighter jobby for the stove
Cool box and freezer blocks or fridge (EHU or gas)
then you can move onto the 'luxuries'
Washing up bowl [contraversial]
Wind break [even more contraversial]
Mallet [forge steel]
Tent carpet
Cobb, bbq or piece of crap cadac
Pimp my tent guff: bunting, cushions, throws, light up dragon flies, flags, wind chimes
EHU
umm
I'm sure there is more....