I own a 94 FZJ80 and I absolutely love it. I don't have much of a commute so I use it primarily for weekend camping and bad weather situations. There is a huge community of support for these vehicles, as well as the 100 series. I would have to say that there is a certain mystique and fanaticism surrounding the 80 series that edges out the 100 series. The biggest concern in regards to the OP that I don't believe has been addressed yet on this thread is price. The starting cost for a stock 100 series is easily double that for a "similarly equipped" 80 series. However, the maintenance costs for the older 80 series can add up quickly due to availability of parts and knowledgable technicians in your area. If you can handle your own routine maintenance and a few weekends troubleshooting, then shop costs might not be something you need to worry about. They stopped producing the 80 series for the US in 1997, which is 15 years ago. There is just a lot of wear and tear on these 80 series SUVs. Additionally it is extremely difficult to find an 80 series in as good of a condition as a 100 series without some ridiculous sticker shock. If you can afford the upfront costs you will have much more luck finding a 100 series in a well-maintained condition within a reasonable amount of time and you won't have to worry so much about sourcing odds and ends over the internet. It took me three months to find my 94 LC, and I can tell you that I will have to put into maintenance about what I spent on the vehicle itself before I start modding it for adventure. Having said that, the maintenance isn't something that I am dreading or avoiding. Go in with eyes wide open. If my budget would have allowed I would have scooped up a 100 series without hesitation just because it would have been almost a decade of wear between the two. That combined with the vast technological advances, makes the 100 series an obvious choice for "occasional adventuring". They are both amazing vehicles. Like Kermit said, you can always drop a SFA into a 100s series to make the coveted 105 series.
As far as what to look out for besides the normal list for any used vehicle purchase, I would strongly encourage you to check out the FAQ for either 80 series or 100 series on IH8MUD and SLEE Offroad's respective sites. They both helped me out tremendously, along with this forum, to figure out what options I needed versus what options I wanted for my specific usage. I can only speak to the 80 series hunt, but the hardest thing for me was adhering to my budget and my need list. There are a lot of guys (and gals) out there who have put a ton of love and ca$h into their 80 series. Quite understandably they want that back when they go to sell them. It's easy to get overwhelmed with "this one has the bumper I want" or "this one just got new tires put on", but in all reality these trucks are insanely overbuilt for DD. Which is why it can be hard to find a low milage one for a reasonable price. Sooner or later though, you can find one from somebody who just wants to dump it and has never modding it or taken it off road. Then the real fun can begin.