[Note: The below opinion is about Expo style fullsize trucks meant for long drives, towing, and some offroad/trail use. Not Jeeps or hardcore offroad toys. I have a trailer for those.]
Any Locker other than Detroit or OX. My opinion differs than most, because I'm reffering to a heavy 1ton fullsize trucks with slushy auto transmissions. I like a Detroit in the rear and OX selectable or open in the front. Big trucks handle excellent IME with a full case auto Detroit Softlocker. As long as you have weight, good tires not slippery (in the snow) Mud Terrain tires, and a wheelbase no shorter than a regular cab long bed. I also like how a Detroit can turn and ratchet when needed while still maintaining a good drive forward. I've had trouble turning tight with a selectable locked rear. I want to be locked, but I want to turn as well. Locking and unlocking a selectable gets old fast, where the Detroit just tugs along smoothly offroad for me.
I never use an auto locker up front. I understeer in snow if I do. While I could just use 2wd in the snow.........I prefere to use 4wd when ever the pavement isn't visable. And that makes a huge difference when you consider that I have an auto locker in the rear. The front drive keeps everything straight as long as I drive responsibly. I like the reliability of OX's products. And I allways run tires that have good siping in the winter with lockers (BFG AT, Cooper M&S, Goodyear Silent Armor or Duratrak) I like the Detroits handling onroad. Great if there is sand/gravel on road and if I'm setup right, it's easy to drive. I haven't noticed much bad when towing either.
Obviously a Detroit in a little lightweight small Jeep is a bad idea.
Mud Terrain Tires Great on my Jeep. But on my trucks i can do fine withmore well rounded tires like BFG AT, Cooper M&S, Goodyear Silent Armor or Duratrak. If I'm way out where I don't belong and things are getting too muddy for my tires, or it rains unexpectedly when I'm out in the sticks......I just put a set of mud rated snow chains on. Way more bite than any MT tire I've driven. But not allowed at State Park or Private offroad parks. They'll dig ruts in the trail. I save them only for times where I screwed up and just want to get going, not for play time.
Ham radios or expensive CB's What an expensive pile of broken junk. I had an excellent Galaxy tuned to run on CB. Best radio I've ever used. Crystal clear and powerful. But the bands and channels would change positions, and some channels would also start overlapping. 13, 18, 19 were the same channel. Just too much money into radios over the years. Not to mention the few Wilson 1000's that majikly snapped off.
Now I'll just stick to plain old simple President Lincoln or General Lee radios and a 108" whip mounted to the bed.
Cheap tires
Cheap lift Kits I only run BDS now.
Expensive Shocks I just run BDS and Rubicon Express shocks now. I like their shock valving, same as thier expensive shocks, I just don't expect them to last as long as thier more expensive shocks. But from time to time I dent a shock or hurt them on a hard hit, so I avoid super exotic shocks.
Aftermarket bumpers Way overkill for me. Too heavy, and very expensive. That's money I can use elsewhere to mutch greater effect. I have a ton of small dings in my bumpers, but never really folded one up. I just swap the bumpers out, eventually its really easy to find bumpers for old trucks at scrap yards.
Winches Excellent for off road toys like my Jeep YJ. But all I need is chain, a highlift jack, and a shovel. It takes longer to dig, but it allways works. Winches don't like snow/salt/me that much anyways.
Can't really get a 1ton truck unstuck without jacking it up and digging even with a winch anyways. At least not without a ton of force which makes me a bit nervous. I'd rather not pull on any cable with 15,000 pounds of force if I can avoid it. I've only got two arms left and would like to avoid haveing one sliced off by a broken winch cable. Not too mention that a winch is a ton of weight on an allready heavy vehicle.
Roof racks and baskets The pupose built 4x4 racks are way too expensive for what they provide. Better off making my own. The basket is expensive and nearly useless, everything up there gets bolted down anyways. I find it better to get a steel ladder rack and chop and weld my own braces and beams in to fit a pair of tire mounts, , shovel, jack, axe, and a (empty) Pelican case or two. One for my chainsaw, other for recovery gear. All my camping gear goes into soft packs that can be stuffed anywhere anyways. My bags are all lined with HD garbage compactor bags or trash bags anyways if it rains. I do like to keep everything mounted to the insides of my bed or on a rack. I like haveing as much room on the bed floor as possible.
I have to chop roof racks up anyways. I like to have removable top bars so I can walk/ride motorcycles into my truck. That means I haved to strengthen the sides and front of the racks. But I've seen many drivers start a custom build with something simple like this:
http://www.discountramps.com/surefit-universal-truck-rack.htm
Any axle gear ratio less than 4.30 People have been offroading succesfully, crossing continents like Africa, Antartica, US, and Asia with a whole lot less power than 300hp 400tq for many years. Yet so many people complain about a GMC 6.0's, Ford 5.4's, or 6.8's power output? Don't fear the gear. I have never lost much mileage with gears. At least not compared to heavy tires and non-aero lifts.
I like 4.30's for stock truck tires, 4.56 for 33" and 4.88 for 35-38" tires. Totally wakes a truck up.
Any tire larger than 35" That's the line for me between useable and practical, vs. offroad rig. I can get alot done with that size, without loseing too much drivability. And it's $$$ to go bigger anyways.
Any lift over 4" I'd rather stay low and chop the fenders as needed for larger tires. A 4" lift on a fullsize truck isn't exactly low anyways.
Carpet and leather Seriously? What was I thinking. Rubber floors with drains for me!
Aftermarket wheels Stock or cheap steel wheels an inch wider are all I need. And look good in black.
Seat covers, even good ones Just money wasted that I could have spent on new seats that really freshen up an old truck. If I'm mudding/camping I'll throw a bedsheet over the seats.
Engine mods 2003+ trucks are plenty powerful.
Aftermarket ignition products/computers allways less reliable than factory parts. Used to eat Autozone ignition modules and MSD coils after I replaced my failed factory components. Nothing but trouble. Now I run factory parts and have seen a ton better reliability.
Factory stock brakes Warp city, cheap steel. Napa has thicker rotors that work best for me.
Dual battery controllers Junk that'll just fail and connect my main engine battery to my aux battery while I fall asleep at camp with my goofy tent lights and radio running.
I use a Deepcycle group 31 in the bed. And I connect it to the main battery in parallel with a starter relay on a switch in the cab. When I park the truck I switch off the relay isolating the battery in my bed from the truck. All my accesories, CB, laptop, AC/DC inverter are on the aux battery. When I hit the road, once I make it to the freeway I switch on the relay connecting the aux battery and letting it charge off the engine alternator. No fancy gauges, nothing. For long trips I'll put in two 31's or a 8d battery if there is room.
Todays electronics have a ton of parasitic load. My laptop for my Delorme software loves to boot itsself up in the middle of the night. Making my ride glow like it's been invaded by aliens. I only drive my personal cars on weekends. Having everything on that isolated battery keeps my trucks wiring close to stock once I flip that switch for the relay off. I can isolate the Aux battery for cleaner power to my CB as well.
Electric coolers Haven't found one that works better than Ice from a gas station. Have to fuel up every 500 miles anyways.....