Damn.
If you're in a rough-and-tumble neighborhood, it helps to travel light, which means taking any unnecessary valuables out of your pockets or bag or purse. It might also help to carry a fake wallet with some of those fake credit cards that come in the junk mail and maybe a few dollars in ones and a five.
Very important:
1. Always keep a written backup copy (at home) of the personal information on your cell phone.
2. Always keep a written list (at home) of everything that's in your wallet, including the important information like debit card details. I actually have a photograph of both sides of everything in my wallet (other than the money, obviously).
This way, if you ever lose your phone or your wallet, you'll not have lost any important information, and you'll also know who to call. (For every card in your wallet, you'll have to call the company involved, take any necessary security steps to protect your accounts, and have new cards sent out.)