I must say that I am embarrassed of all of the morbid thoughts which I had associated with Rio. I had an absolutely amazing time and was really surprised of how "normal" the city really is.
I packed nice but casual, no jewelry, nothing too flashy. However all of the clubs which we went to, the women were very dressed up from head to toe...dresses, heels, jewelry...I was really annoyed that I left so many things at home!
I went to Copacabana beach a few times and didn't feel threatened in any way, I was surrounded my many carefree families just enjoying the sun and water. I even stayed there for a few hours myself one day and still felt safe. I also walked around Copacabana by myself to look for some souvenirs and I felt fine, I just walked like I was any other local.
As for the night, I was a little bit nervous walking around as we looked for a cab (when no other people were around) but I would also be nervous if I was in a similar situation in Toronto.
I had expected the beach area to be a scary place after 9pm but to my surprise it was well lit and tons of people were walking around. We obviously didn't go onto the beach but it did not look as dreadful as I had pictured it to look. Every night you could see teams playing volleyball.
We spent two nights in Petropolis at a beautiful resort that was 2 hours north. I wasn't sure how safe the drive would be but we stopped numerous times for directions and the locals were super helpful.
New years in Rio was awesome, the fireworks were spectacular and the parties were awesome, the streets were filled with people all throughout the night! It will be a new years that I will never forget.
Anyhow I just wanted to say that if you are thinking about going but are unsure because of safety concerns, don't bother just go and have a good time. Fine the crime rate is higher there, but if you think like that then you are not really safe doing anything in this world.