Well I probably should have titled this thread "must have gear before hitting the trails for the first time." ... I was really just thinking along the lines of preparedness, not performance enhancement.
I did sense that, but I answered according to what you had written mostly for the benefit of the novice or newcomer. (I neither want to play nor prey upon their jejune concepts of what a
true Jeep or a
true Jeeper must have or be; rather, I want to just encourage them to get out there and enjoy what they have.)
As to what specific gear to pack, I guess that would depend on where one was planning to wheel and for how long.
Folk such as Cascade Wanderer, BRUT4CE, Bonecollector, and Highlandman (merely as examples) would quite likely choose different items as different terrain, weather, and intent would require.
But there are some basic categories worth consideration:
Communication
Cell or satellite phone, CB, flares, etc.
Recovery
Tow hooks/shackles, Winch/come-along/hi-lift, straps, tree-saver, gloves, jumper cables, tire repair kit, tools, duct and electrical tape, WD-40, shop towels, knife, shovel, axe, flashlight, oil, coolant, reserve fuel,etc.
Survival
Food, water, rain gear, blanket, first aid kit, fire-starters, compass, firearm (if, and only if, absolutely and unquestionably necessary please), etc.
Enjoyment/Comfort
Camera, change of clothes, mosquito repellent, batteries, hat, sunglasses, toilet paper, enthusiastic and compliant member of the opposite sex, etc.
And, of course, all of the bags in which to separately stow this gear.
The specific items vary from trip to trip, but I always travel with the relevant items from these basic categories. (Hell, I even have a duffel with winter bib-overalls, heavy parka, insulated boots, serious mittens, thick wool socks, full face wool, and sunglasses in the back just in case I break down on the one hour drive through the barren and frozen countryside on my winter way to work and back.)
But I still couldn't say that much of this could be counted as must haves before 'hitting the trails for the first time'.