If I were you (and will be in a few months), I would start off by going through the entire Jeep and performing a full tune up and maintenance first before throwing mods at it. That way, you know what you have, how to work on the Jeep a little and bypass some of those annoying issues that can crop up.
-Change the oil, diff grease, xfer case, tranny, engine oil and coolant (flush). Inspect fluids for anything out of the ordinary.
-Check your coolant hoses, thermostat and radiator. Replace as needed and pick up some spare hose and clamps.
-Change the fuel filter and check all of your fuel lines for rust and/or cracks.
-Pull a spark plug or better yet, change them 'cause they are cheap.
-Inspect the cap, rotor and plug wires, or better yet, just replace them 'cause they are cheap too.
-Check your vacuum hoses and wiring for anything cracked, broken or rigged. Fix splices and secure anything that is hanging loose. Nothing sucks worse than electrical and vacuum gremlins that ruin your day.
-Check your u-joints in the drive shafts and verify they are in good shape (I would replace them anyway before installing a lift with greasable type)
At this point, you would have spent some money but have gotten dirty and know the ins and outs of your Jeep. You never know what the previous owners have messed with or not done like they should.
I performed this on my old Land Cruiser and you would NOT believe the crap that I found that was hidden from view. I ended up having to re-wire most of the back half of the truck because of how many splices and rigs there were. I also found a u-joint that self distructed in my hands, an oil seal that would have gone any day, and enough other things that made be feel real good about taking that time.
Now you are ready to throw mods at it.
I second this heavily.
U neglected to do this on my last YJ and regretted it constantly as problems seemed to arise daily that could have been found and resolved had I just took the time and spent the money to look and fix them preemptively.
With my lastest YJ this has been my plan. I have already done full fluid changes (oil, trans, tcase, different, coolant), cap, rotor, wires, plugs, checked all the ujoints, replaced the battery, and am cleaning up the poor stereo splices. I have an exhaust gasket, fuel filter, and fuse block to still put in. After that I'm confident 99% of future gremlins have been avoided and my YJ will be the reliable DD I need it to be.
Last bit of advice I have is to wheel that thing stock for a while. You'll be blown away at what it can do and have a better idea of what mods you want to do.