Frist aid kit, should include what you would want to put yourself back together. If that's two aspirins and a Band-Aid, so be it. I've found the Costco first aid kits to be a good starter kit. Include survival gear with your first aid stuff, extra water, spaceblanket, flashlight, etc. Be prepared to spend the night on the trail at all times.
Hi-Lift and strap will get you out of trouble in most cases. H-Lift is versatile, and DANGEROUS. Practice using it in your driveway. You said your rig was a Rubicon, so I'm assuming it has tow points already. Rocker armor makes a Hi-Lift more useful, as you can lift the rig from the side.
Skid plates/armor, protect your drivetrain and body.
I'm a firm believer that any wheeled vehicle without a steel roof structure should have a roll cage, not a bad idea even with a roof. Custom weld in, or bolt in. I've seen rigs rolled on a flat road (seriously, I've seen it happen twice). Driver didn't pay attention, drifted up the berm on the side of the road and flopped it.
Check your differential/transmission fluids regularly if you do a lot of water crossings. Axle seals are designed to keep gear oil in, not to keep water out.
Winch, another versatile tool, and also another one that will kill you if not used correctly. I'm not a big fan of cheap winches or hydraulic winches. On the occasion that I need my winch, I usually really NEED my winch. I don't have time to wonder if the internet special winch I got is going to work or not. Hydraulic winches are great severe duty winches, not worth a damn if you are laying on your side and can't run your engine.
Most of all, get out and enjoy your rig. Figure out what it doesn't do that you want it to do. Then build it to meet YOUR needs, not what others think you need.