I'd go with 4.56's. My buddy runs 33's with a 4.0l and AW4. Feels perfect, I think 4.88 would be too low for mostly street driving. But if you spend most your time on the trail, well thats another story.
I run a Detroit in the rear of my MJ and have no problems driving it in incliment weather. I'd buy a Detroit for my next vehicle too, no cables, vacuum lines, or electric switches to worry about. It works well, and it's very dependable.