I just went last month. It really does depend where you go.
If you go to border towns like TJ, Ciudad Juarez, or others and do stupid things like drink, look for prostitutes and drugs- I would feel scared to. Some (tourist) towns, (I've heard, but can't say for sure) are also heavily inundated with bad guys; I've heard Acapulco and Puerto Vallarta and others. I went to San Felipe, and felt entirely safe the whole time. But I think Baja California is save because of its geographical location. I still didn't chance driving at night time, and when I went, we went in a mini caravan followed our friends car.
If I didn't have a command of Spanish, had physically light features, and acted like an obnoxious Yankee- I would be scared too. My mother's family are from Guadalajara, and my parents and grandmother were there for a death in the family last month and said all was well as well. I think the further you can get away from the border, the better, but it will also cost more which is tragic. Mexico is a beautiful land, and I long for it and all of its cultural and Catholic history too Kephapaulos. I hope I can get back to Guadalajara one day soon, and visit places like Venezuela and Oaxaca in the future.