I have no personal experience with the Samurai so I'm unable to assist with gearing suggestions - I know that the transfer case gearing impacts high range, so it is one of the options open to you, axle gears are a second option.
Having made that clear, I want to add this before I "fade away" - personal experience with bigger, heavier & more powerful vehicles suggests that anything over a 5% change in gearing due to larger tires IS noticeable, you feel it in the acceleration, you feel it when climbing hills - a 235/75R15, which is going to be almost 19% increase over OEM on a Samurai, which is considered by many to be underpowered off of the showroom floor, is going to have a HUGE impact.
Will it be "enough to make you hate yourself"? In my opinion - YES - but, consider that an "uninformed opinion" and take it for what it's worth - personally I would not consider going over 9~10% without addressing the gearing..