I was thinking, while reading this thread, that what many people need to be able to read, is a reasonably accurate explanation of what various radios are capable of,,, and with a reason of why.
GMRS and FRS are both in the UHF radio band and cannot transmit beyond Line of Sight. This number is affected by height of the antenna not by power. Which causes two hand held units to only be able to talk aprox. 1-2 miles under the best conditions on level ground with no obstructions. Trees, buildings power lines all work against you in achieving that distance. Change the hight on either radio will change the distance. GMRS requires a federally issued license, and requires renewal but has no test to take.
MURS is a VHF radio band, does not require a license, and has about the same transmission distance. But the radios are significantly more expensive and are limited in their power output.
GMRS and FRS and MURS are great choices if you are going to be talking a very limited distance.
CB with only the legal 5watts (or 12watts if you get a side band version) will give you greater distance. With the external antennas being about to be higher and the base antennas being able to be both directional or omni directional can give you greater distance. Most "mobile" setups are estimated to be able to talk 5-10 miles depending on the terrain. In city and suburbs, even these distances might be hard to achieve due to electrical interference and buildings in the way. Because these are in the HF band, their radio signals have the potential of reflecting off the upper atmosphere and "skipping" for long distances. These are not consistent enough to be trusted for day to day communication. Higher antennas, and directional antennas will give you markedly farther transmission more consistently. How far is hard to estimate and can be very site and direction specific.
With all this being said, The benefits of operating with ham radio gear is several fold,,, and I'm sure others can add a lot more.
Ham radios often allow more power, better antenna designs made for longer and more consistent communications. The limitations of VHF and UHF are bypassed with the use of locally installed repeaters. Because they are often installed VERY high they can receive a weak signal and retransmit it to a much larger area. If you are talking a serious grid down scenario, if these repeaters are down, you are once again limited to a relatively short line of site transmission on these bands/frequencies. Please, lets not argue about the potential of skip and ducting (a form of skip) because they are unreliable for consistent communications on these bands.
If you are looking for long distance communications, HF is where you want to be for consistency. CB is in this group but the power limitations really hamper it's ability to talk distance (legally). Where as, many ham radios in the HF range are allowed more power. And after using them for a while you will discover that some frequencies are better during the day and some at night. Very often, with only 100watts and a home made wire antenna suspended between a couple of trees these radios can consistently talk hundreds if not thousands of miles. With a general license, you are allowed on most HF bands, over 1,000watts of power. These signals can skip (propagate) all over the world.
Anyone can buy ham radio gear, but you are not allowed to talk on it with out a license. To take a test it costs about 15 dollars per test and there are three levels I believe. Tech (mostly for UHF and VHF and a very small sliver of HF), General (UHF and VHF and HF (minus a very small sliver) and Extra. which opens up all the ham bands.
The biggest advantage of having your ham license is being able to talk and get use to the equipment before an emergency happens. How far will a signal go? How clear will it be? This are all things that you can test on a daily basis once you are on the air.
What radio would be best for what you need? My best answer is, it depends on your individual need. But remember this, there is no such thing as radio privacy.... there is always some one out there listening. One article I read gave the number,,, if you are talking to one person,,, ten are listening,,, if two,,, then twenty are listening.
All I really wanted was to live a simpler life. The future I see coming at us like a freight train will be anything but a simple life after it hits!