I think it's all going to depend on the area you live in and reasons why you think she might need one vs. her just wanting one. To me there are more pros to kids having a cell phone with a very restricted plan. DD is only 5 so at least we have a few more years before this discussion comes up. When she enters middle school I'm pretty positive we'll be buying her one, with restrictions. That will be in 7 years so who knows what technology will be available by then anyway?
To answer the question of another poster regarding what I did as a child before cell phones (in the 80's and 90's.) I would tie up the house phone (this was when call waiting was an unneeded perk and considered new technology) for hours on end. If someone had a teenager you planned on not being able to reach anyone else in the home except very early on weekend days.

I would go outside and play with my friends (this was a good thing) and then when it was time to come home, I would be late using excuses like I didn't know what time it was, the streetlights weren't on where I was, etc...(now that I know the extent of parental worry I see why I was in trouble so much.) In high school and on school trips, some overnight, I was told to call collect to let my parents know I had arrived safely. I often forgot or just couldn't find a phone. If you're skiing finding a phone on a mountain isn't an easy thing to do. School buses run late, it happens a lot. Often I would return to school to find worried and angry parents to get into a car with. If I'd had a phone this could have been avoided.
The main reason I'm in favor of cell phones for teens to use responsibly is the few times I found myself with my friends in a situation I knew wasn't right. I wanted to do what I knew I should and call my parents to come get me, or use them as an excuse why I had to leave. I couldn't. No way I was going to ask to use the house phone and call mommy and daddy. So I tried to stay out of what was going on (ie drinking) by not participating, but yet now I see the danger of what could have went very wrong by staying in this situation. If I could have just sent a text to my mom to come get me, I could have blamed having to leave on my parents and gotten away without having to consider peer reactions. Of course I survived, and turned out just fine without one, but so many issues could have been avoided. Now being a teen I'm sure I would have found other issues to get into trouble over,

but at least the ones where my parents had to worry about my safety could have been reduced. I wasn't a teen that had a rowdy group of friends. We all were honor roll students taking college prep and college level classes, never in trouble in school or any of that. Yet I still found myself in situations with what would have been considered to be the "good" group of peers that could have went very wrong in a hurry.