It really depends on personal preference and where and how you plan to use it, but my vote goes in this order. If youve already got the lift on then (for me a lift goes in right after skid plates but youve already got that), tow points, skid plates, winch, locker or limited slip, regearing, then bumpers and tire carrier. The list can get muddled some when you start looking at bumpers because with them you can kill two or three birds with one stone, ie: a winch bumper with tow points or a rear bumper with tow points and carrier. Be prepared to spend around $1400 or a decent front and rear bumper, unless you can do your own fabrication. I chose to keep much of that $1400 in my pocket (actually most went to regearing) and go with a rear receiver hitch and this
http://www.detoursusa.com/images/xjbackbone05.jpg
on the front.