The merit/hella plugs all the way. Not only are they rated at a higher amperage (Rebs, I don't know what caused your issues, but these are better than the standard fridge plugs) but the fact that they lock in, and the sockets have dust caps standard make them far more reliable.
Cig lighter plugs are ok for temporary use of a single item, but to try to have anything plugged unattended for any period of time and you can be sure the cig lighter plug will loose contact. Though the high quality cig lighter plugs are not too bad, just about everything these days has the cheap and nasty cig. plugs.
As a default position anything that comes with a cig plug I replace with a merit style connector, and as everything I have is now merit type there is no compatibility issues. I also have a couple of merit->cig adapters for times out camping where I come across anything that isn't merit, but most people I travel will are also exclusively merit these days also.
There are also better options out there than the merit plugs for better moisture protection and power handling capabilities, but as a standard basis they are perfect for our needs.
- David.