Rock rails, fuel tank skid, trasfercase skid, and the engine skid first. Those are the essentials, any damage to those componets will run you into the thousands for repair, except the fuel tank but you don't wanna be leakin an explosive liquid all over the place. The engine skid covers front diff, part of the oil pan and the steering stuff.
Get a skid row for the front. It has better clearence and is thicker than OEM skid. Once my OEM front skid is toasted I am going to get the skid row one.
Need the rocker rails cause you do the rocker panel you won't be able to open/close doors and the repair bill will make your eyes water.
The engine/tranny skids, either skid rows which I have or all j's, (superbeefy but harder to install) cover the rest of the oil pan, the tranny, tranny oil pan and the front of the transfer case.
It bolts under the engine skid and over the transfercase skid so you have solid skids till you are behind the transfercase.
I like this plate as well for keeping brush and rocks away from the boots on my drive axles.
www.skidplates.com is for the skid row plates. They got a buch of pics so you can see what is covered
As far as the rails I have RRO supersliders. I bought them first before I knew buying from RRO is risky business.
I like the rocklizard superslinks they look really beefy. Anyone who owns these? Sweet? OK? Pain the but to put on?