Cruising gurus Lin and Larry Pardy were advocates of no electronics, period. I don't think that will fly today, but electronics are a major source of headache. Friends I met on the trip set out for Bermuda in a 37' steel boat and in their first storm all the electronic got wiped out and they decided they had to sail back. All connections should be soldered, not crimped, to avoid corrosion. I went through my whole boat and soldered all the connectors and never had a problem.
When talking to others the most frequent electronic failures related to solid state converters for A.C. refrigerators which failed frequently. Also, solid state cooling units had a high failure rate. The best refrigeration units were those where the compressor was run off the engine. Refrigeration requires a lot of power. Either engine, solar panels and wind units, or all three.
If you don't have refrigeration (make sure you have a well insulated ice box), one small solar panel will provide all the power you need for radios and lights. Ice is available all over the Caribbean, though prices vary.
Solar power is great down south. I had one 12" x 9" panel and it provided all the power I needed for lights, radios and navigation gear. The salt water had no effect on it at all (it is completely sealed in epoxy.)
GPS, now so inexpensive and reliable, should be considered a must. A good depth sounder and log is a must too for the Waterway etc. VHF is of course essential and is used as an open 'telephone' line between boats in the Exumas and other parts of the Bahamas and was very useful.
I carried an EPIRB too and these are getting cheaper all the time.