Trasborg:
For me, a mud tire is where it's at. Even on a Jeep I am trying to get mileage out of, I will gravitate to a less aggressive mud-terrain before seriously looking at an all-terrain. Everything I have ends up off-road, often far from anywhere or anyone, and for those situations, I'll gladly take the trade-off between fuel economy and tire wear to make it so I'm not going to get stuck because of not having big enough voids. One off-road tow bill could easily buy a new set of tires.
As for rims, if you want to air down, bead locks are where it's at. But often living with bead locks on a daily-driven Jeep is a pain. Keeping all 150 bolts tight, maintaining air pressure, dealing with stick-on weights falling off... I like the simple steel wheels. They take hammer-on weights; if I destroy one, I'm only out 40 bucks to replace it; and for the most part, I can go down to 8 or 10 psi without blowing a bead off.
Armor/Recovery
Cappa:
I know I've said it before, but rocker guards are the number-one mod I would make to any Jeep I plan to take off-road. It just doesn't make any sense not to have 'em when you consider the cost to repair this area when it gets damaged. Avoid overly heavy and overbuilt bumpers and skidplates and look for well-designed parts made with quality materials. Solid tow points front and rear are a must as well. I like to wheel alone a lot, so a winch is also high on my must-have list. If you find that you most often go wheeling with buddies, then you may feel differently since you'll have a pal to pull you out. Oh, and every Jeep needs at least a 20,000-pound-rated tow strap before it hits the dirt.
Hazel:
For me, one of the best areas to throw money at is products that increase your trail survivability and ability to get unstuck. For most rigs, that means skipping the lift, lockers, and tires and going straight for undercarriage and body armor, followed by a good winch. With armor you can scrape rocks and obstacles all day and with a winch you'll be able to extricate yourself from anything your low-slung suspension can't get you over.
Trasborg:
I'm a big fan of overbuilt armor. For me, 3/16- and 1/4-inch plate steel is a good thing anywhere rocks might hit. I've also been known to use plate steel in my aforementioned rusty-sheetmetal repair. The more metal there is, the longer it will take to rust through. As for recovery, I always try to have at least a 3-inch-wide, 20- or 25-foot strap and D-ring shackles in whatever Jeep I drive, regardless of if I plan to get off the pavement or not.
Steering
Cappa:
Aside from necessary drop pitman arms and such, much like Hazel, I'll typically put my money into upgraded and beefier linkages before I cash out for a more powerful steering box, pump, and ram assist system. However, once the stronger parts are in place, the addition of a ram assist is a great way to keep an overloaded steering box alive. Heavy rock use with 35-inch or larger tires puts a lot of stress on the steering box internals and sector shaft. A broken sector shaft is very difficult to repair and will stop pretty much any Jeep in its tracks. A ram assist helps distribute that potentially damaging load elsewhere. If my off-roading doesn't involve rocks or tires in the 40-inch-plus size, the steering is pretty low on the to-do list, though.
Hazel:
Another often overlooked but completely necessary area of concern is the steering system. Namely the tie rod and drag linkages, and to a lesser degree the track bar in vehicles so equipped. Upgrading to heavy-duty components will ensure you're able to steer through the trail and continue home without ruining your friends' day while they wait for you to turn your Hi-Lift handle into steering linkages. I'd put my money into upgraded and bombproof linkages long before adding a hydro assist or even upgrading the steering box or pump.