I've owned both XJs and WJs. I'll pretty much echo what most others have said, XJs have MUCH more aftermarket support, but WJs are bigger, more power (if you go with the 4.7 V8), more comfortable, etc etc.
I no longer have any XJs but I still own a couple WJs. One 4.0 and one 4.7. I use the 4.0 for my Daily Driver and it's mostly stock, the 4.7 has 3" lift, 31" tires, winch, custom front/rear bumpers, CB, roof rack, etc etc. It's EXTREMELY capable offroad and MUCH more comfortable than my TJ on the trail.
Around here a clean XJ will run you around $2-2500 while a clean WJ around $2500-3500 stock. If I had a choice to start over and wanted to build a medium duty trail/camping rig, I'd go with the WJ. I fell in love with it after stumbling across one for a GREAT price. Prior to be getting that first one, I always looked down my nose at them because as a CJ and TJ owner, it wasn't a "REAL" Jeep. Now, unless I'm heading out to do some serious rock crawling, I choose my WJ everytime I want to get out in the woods.