I like
Nobeltec VNS. You are about to hear from others who prefer some of the free systems, as well as other
commercial systems. You may want to do a search on electronic charts, chart plotters, etc. to find a great deal of information and opinion that is already on this site.
The present
Nobeltec VNS is reliable, professionally produced, and has very readable charts, and lots of features. Others will favor building their own computer systems and working with self supported free
software.
After reading the immense amount of information that you can find here, you should be able to find what suits you.