Well a steering guard would be a good idea, look for one that has hi-lift sockets and towing eyes too and you're pretty much sorted at the front. Mine has an ali plate so it's lighter than steel ones (though it's missing the jacking points)
If you buy fabricated JATE rings then you can bend them apart to fit over the bumper mounts, that's what I've had to do.
Diffs, you can't really beat the QT style diff guards, these wraparound from front to back and protect the underneath as well as the thinner diff "pan". Fit these front and rear. I've seen the clamp on style slip off when recovering (going backwards) and they don't protect the underside. You can now get a clamp on style that also wraps around but I don't see the point. IIRC Paddocks do a QT copy pair.
Back end, the tow hitch will start to get on your nerves. I've seen them cut down before now but eventually I think you'll want a removable hitch, the socket for which gives you plenty of recovery potential. Now if you want a tank guard too then I'd suggest the Southdown style one, speak to Guardian as I belileve he does a very good one in that style.
Next thing I guess is rock sliders or tree sliders. My personal fave is the First Four style, chassis mount only with hi-lift sockets and no tree sliders, but I don't play in the woods.
Put in order for your motor then
Diff guards
Steering guard with recovery
Tank Guard
Sill guards/sliders
I have dan bars but havn't needed them yet, they are still in the packet.
As always I suggest you go out laning with other club members and look at what gear they have bought. Get an honest review from them before parting with your cash.
My vehicle spec is in my profile page, feel free to browse and ask questions