The only things on my phone that could be considered even remotely personal would be my call/text history and my contact list. I guess the calendar, too, but because I rarely have appointments, it mainly contains family members' birthdays and the occasional dentist appointment.
This presented a dilemma for me when cell phone searches first became an issue because if a LEO asked my permission to search my phone, I would have to refuse just out of general principle. But at the same time, because there was nothing there that I'd be worried about them reading, allowing the search would be the path of least resistance; whereas by refusing, I would be inconveniencing myself with nothing to show for it at the end.
My solution to the dilemma was to create three encrypted 7-Zip archive files, with marginally weak passwords, and store them on my phone. They are named "private," "secret," and "personal." One archive contains a PDF version of the Declaration of Independence, the second the Constitution, and the third the Miranda decision.
-Rich