I follow my own advice and run whatever quality synthetic is available for the lowest price. In my case around my area, 100% of the time it's Mobil1. If you want the best, run Amsoil, otherwise, any big brand (Castrol, Mobil, Valvoline, Pennzoil, etc.) Buy the cheapest 100% synthetic and you're golden. Stay away from Royal Purple...snakeoil product.
http://wayalife.com/showthread.php?6985-Mobil-1-extended-performance-oil
http://wayalife.com/showthread.php?11369-Which-oil-do-you-like&highlight=royal+purple
And before people go crazy about my RP comments....the reason is simple...putting aside the fact that they are some of the lowest performing lubricants, in my area anyway, RP costs substantially more than the rest (Mobil, Castrol, etc)....there is simply no arguable reason why someone would want to run a more expensive inferior oil from a company caught lying....just my .02. If you like it, by all means, I am NOT saying your jeep will explode (although there have been numerous examples of engine damage on engines on various forums) but Im not looking to debate that. This is simply meant to be informative, it is your money, and your jeep, so it's your call.