I'd have to vote for a 2nd Gen 4Runner.  The first gen are cool, but they are getting old and they fixed a LOT of gremlins by the early 90s.  (plus ABS, R134A for A/C, and other goodies as well)  Find a 4 cylinder stick-shift if you can - better MPG and easier to work on.

Why?  Because the Jeep *may* be a bit better off-road if you modify it(maybe) - but the Toyota is cheaper to fix and hardly ever breaks.  I'm replacing the transmission on my 87.  It's about twelve years old - and the previous owner beat the thing up.  Not bad for an old manual.  I also can't count the number of Jeeps that I've seen on their 2nd or 3rd engine.  And as for transmissions?  Chrysler is at the bottom for those as well.   For a first car, an older Jeep is asking for lots of money out of your wallet to keep running.

Now, an old I-6 Wrangler... tougher call.  If I was looking at all for a Jeep, it would be this.  Simple to fix and easy to modify.