As a new member I'd like to get started by contributing my experiences. I've owned Liberty (branded as "Cherokee" here in Europe) '05 3.7L V6 for 8 years now, currently at 220 000 km (135 000 miles for you imperially challenged).
This one appears to be designed to run for 100 000 miles and not more. If you own similar and have just crossed that mark the sensible thing is to sell it. Unless you really love it (like I do). I've just completed the full tour of all the main attractions, everything listed below occurred within 35 000 miles between 100k and 135k.
The Big One: Cylinder head re-make. The valve guides start to leak oil, I'm not sure is it the miles or the years but, but they will. The oil builds up on cylinders and exhaust valves causing leakage which will eventually give the treaded P030x error code. For some reason it's usually #1 and #6 that are worst, but there's no explanation why it should be limited to those cylinders only. New guides, cylinder head re-tooled and all valves polished. When cylinder head was opened we found out, that those plastic timing chain guides were hardened and one was already shattered into tiny pieces. I'd recommend, that after 130k timing chain set (including chains, guides and tensioner) should be installed, even if your valves are still ok. It's cheap (set cost $129) compared to complete engine blowup which it may cause.
The other "expected" failures I've already run into are water pump (replace every 100k miles), U-joint, front wheel bearings, front right drive axle (both inner rod and outer CV joint). Also replaced one O2 sensor and tie rod end but these were probably just random failure / normal wear.
For bearings and CV joint use only high quality parts, not cheap crap. Bearings should be original Mopar or ***, Timken or SKF. Never ever use cheap chinese bearings made out of material distantly resembling steel. Unless you are prepared to change them regularly, of course. Bearings that don't list original manufacturer are usually cheap shit or more expensive nicely branded shit. My first CV joint was re-manufactured and it was making noise right from the start. Luckily I was able to return it for full refund and get a brand new instead, but the effort to change it twice was lost.
That's about it. Hopefully I can now happily run next 50 000 miles without any major issues (fingers crossed). And I still do love the car.