I was lucky enough to take a six week trip through Central America in mid-2008. I started in Panama, and made my way up to Guatemala. Six weeks was definately not enough, and I could easily spend another six months or more. I missed, although technically touched, Honduras and El Salvador, and completely missed Belize. When I go back, I plan to spend a fair bit of time in Belize and Honduras doing some serious scuba diving.

Central America, as a whole, is a pretty nice place to spend some time. The weather is great, there is tons of biological and cultural diversity, and it is quite cheap. The downsides to Central America are that everything is sorta cheap for a reason - transport is less comfortable, food is sometimes of questionable quality, and a lot of things are in disrepair. The worst parts of Central America are, by far, the capital cities. These tend to be hotbeds of crime and poverty. If you can avoid these, I highly suggest you do.

That said, if you stay out of the capital cities and keep an open mind you will find some of the nicest people and the most amazing rainforests and oceans that exist on earth.