First off, WJ lookin' sick..
Basically what everyone said above ^^^^
I just sold my built XJ to buy my currant WJ that I'm building.
Everything depends on 1) What kind of trails / rocks you'll be running 2) budget, 3) tire size (worth investing in existing axles, or do axle swaps) will you DD the WJ, etc.
If you can afford them, I loved my ARB's (front / rear) in my 01 XJ. Some people have issues with the air lines, but it really isn't an issue at all. You can buy a patch kit & keep it with you. I had the lunchbox lockers in my TJ & personally hated it (for a DD), but they were cheap.
If you want to keep your speedo and other luxuries that our WJ's have you need to stick with WJ type axles as everything works off our ABS tone rings. In saying that, if you have deep pockets & want turn key axles, you can look into axles from ECGS they have JK 44's (front/rear) & D60's, etc that are set to work with our WJ's.
ECGS: ==>>
http://eastcoastgearsupply.com/c-283495-complete-axle-assemblies-jeep-jeep-wj.html
Lockers: Lunchbox (Aussi/Spartin/Lock Rite), Fullcast Lockers: Air (ARB / Yukon Zip Lockers), Detroit (non selectable), Cable OX, etc. (when pricing up my lockers for my XJ, the OX with all the addons ended up being more expensive than the ARB)
The D30's really max out @ 35" tires. People do run 37's and have success, but some guys run 35's on D35's and haven't broken any axles shafts. Me, I snapped my D35 in my TJ on 31's..... I ran 35" GY MTR's on my XJ (HPD30 up front & Crys 8.25 in rear) and I could feel the difference gong from my 33's.
Don't know if I helped, but at least some food for thought. I don't hit trails with Rocks here in WNY & am staying with 33's on my WJ. I'll keep my D30 & lock it with either a Zip Locker or ARB & am thinking of getting the JK44 with an ARB for the rear.