It all depends...

Like most things, you can buy all kinds of radio equipment but if there's no one listening, what good is it?

Marine band radios are great, on or near a boat. You won't be raising many people using one on dry land nor is it legal to do so unless in an actual emergency.

As for GMRS and FRS and MURS, same thing, who's going to be listening to you and what do you want to communicate to them? You also have some pretty severe transmitting issues with GMRS and FRS radios in that you're limited in wattage.

CB's are ok for what they are, but again, who's listening and what good will it do for you in an emergency?

The only viable alternative is Ham radio, with a pretty small investment you can get up and running on the 2 meter, 220 and 440 bands and you'll be able to actually make contact with people. A small handheld radio with a simple antenna mounted on the roof will give you the means to at least hit a repeater and theoretically get a message out. You might also be surprised at how many people are Ham operators out there. In addition, unlike any of the other accessible radio formats available to you, there are people in Ham radio who actively monitor and help out during emergencies. Do a Google search for a local ARES group to learn more. The test for an entry level technician's license is pretty easy to pass, there are numerous online resources that can help you. While it's true that you can spend thousands of dollars for Ham equipment, there's no reason to do so if you're only going to be using it in your stated limited fashion. I've got a mobile radio in my car and a handheld and together, including antennaes I've spent less than $1000.00 and I am an active Ham operator. You could get set up for far less.

And yes, it is possible to transmit using satellites and an amateur radio. It's even possible to do so with a handheld radio and beam antenna, it's not something that your likely to do on a whim but it's very much possible.

John E