Living in sunny SoCal, I think tint is a necessity both from a heat and security perspective. That said however, I wouldn't tint my front windows very much, as visibility at night is of high concern, and the tint will definitely make a difference.
I personally went with Formula One film, installed by The Tint Pros. 70% front, and 15% rear (which combined with the factory tint yields about 8-10%, i.e. Limo) and I couldn't be happier. Heat is drastically reduced, especially in a car with a black interior, and a fishbowl level of window space. It's also impossible to see into the back seat or cargo area at night, which when parking in LA, makes a huge difference. Visibility while driving at night through the front two is still excellent, and out the back is reduced, but once you get used to it, not dangerous.
Here's a picture: