Modifications in order of importance to me:
1) Tires, 235/75/R15 all terrians in whatever flavor you think is best.
2) Front tow points.
3) Rear tow points.
(Note: new bumpers are better than the other options available when it comes to tow points. Save some money up, look for bargains, and bite the bullet. You'll be happier in the long run me thinks)
4) Gas tank skid plate.
5) Any other skid you can come up with.
6) Upgrade the rearend. Minimum Chrysler 8.25 and a lunchbox locker or LSD.
6) Lift but only after 1-6 are done. The first thing many people do but as you can see it's way down my list.
'89 YJ (MC Carb, Nuttered, 2.5" OME lift) & '98 4.0L ZJ (2" BB,KOR Rad. Support, 31" BFG 's)