What's your budget? Jeep used crappy gear ratios with the 4.0L (yes, 3.55s suck in my opinion, especially with a stickshift and 33s) until the Rubicon TJ came out. Since I imagine you're keeping the Dana 44 axle and regearing, I would plan to regear both axles to 4.56.
What I would look for:
non-CAD front axle, preferably with the 297 U-joints
AX-15, preferably with the external slave
23 spline np-231 to match (or 242 if you want the AWD option)
It is possible to get all these on a single XJ