I guess the engine makes quite a bit of difference...I was shocked to read people pushing it in the 70's range and feeling like their Jeep was going to come apart...then again, I've got the 4.0L in my '97 TJ and I can easily get into the 90's cruising down the freeway comfortably and safely - even with a lift and 33's. A little less power now that I switched axles and went from 4.56's to 4.10's, but still find myself in the 80's and 90's on the freeway. (We drive fast in CA - I've lived all over the country and world and California drivers are good with speed for the most part relatively speaking). I had a '91 YJ with the 6-cyl and 31's and I got pulled over for going 105mph...I told him a Jeep couldn't possibly go that fast so his radar gun must be off and he said I was probably right and marked it down to 85 on the ticket. (I knew full well I was going 105mph - I had a friend in another car clock me since the speedo only went as high as 100). I don't drive that fast anymore - but I do drive pretty fast. My problem is that I get rental cars for work trips all of the time and I go wayyyy too fast in those and don't realize it....you definitely feel it in a Jeep.
I think we should have had people qualify their response by listing engine size and gearing, etc. It makes a huge difference.
When I was driving my TJ for the first time back from Arizona (bought it on ebay), I did 85 The whole way, occasionally 90. It did it very smoothly and comfortably. I've gotten it over 100, wasn't that bad.
1990 YJ-The wheeler
2015 JK- The DD