I read a lot of forums about travelling through south or central america, and to be honest, not many reports want me to go there, as they where always really negative and scary! who knows this places and has been travelling through them reasently???
I have travelled through South and Central America twice so far (the last time was christmas/new years last year) and never had any problems or scary experiences at all. All I can advice you is to use common sense and you will have a great time. If you are afraid of going to Latin America don't go as people will notice and you become an easier target for potential danger. I can only tell from my experience and I would return any day .
Steff has given you very good advice...If you are aware the right people notice and leave you alone..if you are paranoid it attracts theives and muggers like flies..vibrations...this is street smarts. If you find a travel companion who knows Central America and speaks Spanish he or she will soon tire of having to ask questions and do everything else for you. I have seen these scenarios before. It is your journey. You decide.
There's a number of other threads on this issue already; read those, and don't worry. With the usual safety precautions, most of SA is completely safe (and most of the unsafe parts are hard to reach anyway )
I travelled trough costa Rica, Panama and parts of Nicaragua, I felt safe most of the time and as said before, if you use common sense then you should be ok!
I only had one incident while I was there and that was that I had my bag stolen, I fell asleep on a bus and when I woke up my bag had gone. That was as I was entering San Jose where you are supposed to expect crime although, it was really my own fault, I shouldn't have left my bag in such an easy place!
Anyway, what I am getting at is that I never felt in danger. I don't think anyone should put off visiting Central America because they have heard it is dangerous. Just make sure you have a working knowledge of the Spanish Language and be as street smart as possible!