Oh boy! I bought mine almost a year ago! I have done a lot of things, but last week I:
1) Installed the Tow Hooks on the front bumper. With a little googling you can find a writeup on how to make it really cheap. Its really worth it.
2) Replaced the Thermostat Water Neck, Serpentine Belt, Replaced the broken/rusted Heater Return Tube with a Tube/Hose i made (I shoud do a writeup about that...), replaced the transmission fluid and filter, replaced the bearing of the AC Compressor Cluth.
3) Disconnected the sensor of the glass on the liftgate. To all the 98' ZJ owners out there: if your VIC keeps telling you the liftgate is open or your battery keeps draining all the time or the alarm goes off randomly when parked, kill it. Disconnect it, now! everytime you close the rear glass, it pushes the sensor, moving it to far and preventing the BCM to go in to sleep mode, draining you battery. Pushing the sensor back into place only works for a couple of weeks, so I really recommend doing this. And in case you are wondering, the glass will still be functional (closing, opening, locking). Just do it!
Now I have to replace the timing chain and replace the suspension control arms.