Royal Purple XPR 10W40 or Royal Purple max cycle 10W40, just check and make sure it's not rated CJ-4, CJ-4 rating lacks the zinc and phosphorus levels the cam and lifters need to prevent premature wear. You might even find Shell Rotella synthetic that is not rated CJ4, shell told us that they are not due to remix their stuff for another 3 months. Might also want to find some GM EOS if you can, GM stopped making it, it has the added zinc and pho additives. A lot of this is still up in the air as far as blackstone and Staveley are concerned and it's being hashed out on about 4 or 5 forums. Rule of thumb is the 'old car' type oils still have the additives that our old style engines need while the CJ4 rated stuff does not, the removal of zinc and pho is supposed to extend the life of the cat converter.
I'm in the same boat you are, all three of my 97 and 98 jeeps run mobil-1, thats going to have to change so I'm down to my last few 5 quart jugs of M-1 10w30 and will be switching over to royal purple. Both AA and National parts [not napa] have both started stocking it for this reason, they never carried it before but I will be staying with K&N and Mobil-1 filters though.