A lot of states say zero tints on the front. Best thing to do is go to an eye doctor and try to get them to write you a script to allow you to get your windows tinted. A lot of states have medical exemptions if you are light sensitive.
If you cant pull that off just do it 50% you will notice a huge difference even though its still easy to see through. I have 20% in back and 50% in front a lot of cars come with dark tints now like the new Dodge Magnum and a ton of SUVs so dark rears doesnt phase cops. Even with light tinted fronts you probably wont have a problem, they will pull over the kid with the 92 civic with the coffee can sized exhaust tip instead.
4meezy - Do a 35% tint all around and if your that worried, do a 50% all around. I had mine done (35%) over a year ago and haven't had any problems in NJ (And I drive all over this g-damn overcrowded state! :weirdo: ).
Many of the laws are passed for the safety of the driver as well as law enforcement officers. For the drivers to see clearly and not have the dark shadows or effects that tint will have. Officers hate the dark tint, because on traffic stops they need to be able to see what is going on in the car when they are walking up to it. They don't want to be surprised when they walk up to the window no matter how minor the stop is. That is what I have been told on my internship's with the local Police Departments.