You may get a lot of differing responses to this one.
But, IMHO, the FJ40 makes a poor daily driver.
* They are simple trucks but constant daily use is going to wear stuff out.
* They are not great on the highway as a commuter: poor mileage, bouncy handling, lousy aerodynamics and very noisy. Forget listing to the stereo at highway speeds.
* They are not great in city traffic.
* They could become a target for thieves if they are out and about everywhere. They are easy to break into.
* They are just not that comfortable to sit in for long periods or constant use. It gets worse the taller you are.
But, IMHO, the FJ40 makes a GREAT second or third car!
* Nice to drive around in the summer with the top off.
* Great 4x4 off-road rig, perhaps the best ever made.
* Great rig to take camping, fishing etc.
* Are more fun when driven recreationally. All the negatives I listed don't seem that bad when you are having fun.
* Superb platform if you desire to build a serious wheeling truck.
In the end it is hard to build a 40 that is great on the highway, is comfortable, is quiet, and excels on the trail. Its possible to get close but it takes cash and effort. Most 40 owners make up their mind and face the choice: is the truck going to be mainly a serious 4x4 off-road rig or is it going to be comfortable, tarmac friendly show piece that hardly ever sees any low range off-road use?
The 40 was designed more for off-road use: the early models were never designed to go 70MPH and they never really got that refined. Gas prices are already way high but they could go way higher. So, for daily driving or commuting I would buy something else. If you really want a 40 then try to mainly use it for fun: you will enjoy it way more...
Cheers,
Max