There has to be two answers for this question.
If you are maintaining a job at a fixed location; then, the best place to live aboard is with a reasonable priced dock
at a marina with all the amenities at a location where there is quick access to anything cruising after work in protected water
and access to a safe inlet for offshore vacation
cruising. For us this was the St. Johns River in North Florida
If you are retired or able to be mobile with your work; then, the best place is a range of latitude that allows you to adventure in the best of weather
. For us this is from Maine
to the Florida keys
Others have great liveaboard
locations with a huge longitude range.