My fear is this turns into something that gets in the way of people participating in the hobby.
Think of comms as a necessity if you plan on going out with one or more other vehicles at any point. You want to be able to reliable and efficiently communicate with others in the group while in-vehicle. Note that this is different than having emergency communications devices like an in-reach. With a radio in the rig, it's primary use will be to communicate with other people in your group while on a trip. This can be conversation, turn notifications, or things like "are you hungry? should we stop for lunch soon?" "How are you doing on gas?"
The end-goal should be to
eventually have all three radio types, but by no means should you get them all right away, unless you like spending lots of money in large chunks! If i were to suggest a priority for going from no comms to full comms, i would say:
1) Get a GMRS radio/license first, as the license is easy to get (no test, just pay the FCC) and the sound quality and range are great. The reason i suggest this as the first, is that you can also pick up some FRS radios to hand out. If you are on a group run, and people don't have a GMRS radio, or even comms of any kind, just hand out some FRS to people who need them and you're off! Often times, GMRS handhelds are sold in packs of two, so right out the gate you'll have one extra radio (set it on low power if you give it to an unlicensed person to borrow)
2) CB. The sound quality is crap, and the range is typically terrible (in canyons/valleys especially), but unfortunately, CB radio is king of the trail in most areas. Chances are most of the people you will go out with will at least have a CB radio. Don't spend a lot of money on a CB, because you may hardly use it. I have one in my rig, but i probably only use it once or twice a year tops.
3) Finally, after you have the other two, strongly consider spending a week or so studying for the amateur radio Technician license, and go take the test. It's quite easy especially if you just focus on memorizing the question pool. I know of 9 year olds who have their Extra class license (the third and most difficult of the exams), so don't listen to anybody who tells you it's too hard to pass Technician. Once you have your ham license, this is where you'll wanna eventually drop some money down on a nice radio for your rig. The sound quality, range, and feature set really cannot be beat.
In my case, the order of how often each gets used is: Ham (by far the most used for me), GMRS, and CB (rarely ever gets used)
Long story short: Don't worry about diving super deep into the radio stuff right now, just pick one and go with it, but consider planning on
eventually having all three if you plan on joining group trips at any point. Also talk to people in your area, the radio of choice is usually a regional preference, so some areas may be almost exclusively CB, and other areas may be almost exclusively ham. If you talk to people in your area and they all use CB, then get a CB first and ignore my priority suggestion above
If your plan is to continue only doing solo trips, skip GMRS and CB, but still consider ham, as it's the best option for emergency communication should you find yourself in a bind. If you are solo, you are probably primarily interested in comms for some sort of mishap or breakdown, so strongly STRONGLY consider getting a SPOT or In-Reach, or even a sat phone.