In all my travels around the world, I've always had the comfort of knowing that if my pack were stolen and my room was robbed, I'd still have some cash. That's because I've always worn a belt that has a secret zipper compartment in the back. (I know, I know--if you see me on the streets of Quito now, it's no secret is it?)
These things will literally hold hundreds of dollars without anyone being the wiser. You keep a few ready bills in the local currency at the ready for shopping, keep the rest under your clothes, and then some big bills in this thing. If you manage to get all three ripped off, you've got the worst luck on earth.
The ones I have (I bought a spare) are brown canvas with leather where it buckles. Apparently they don't make those anymore, so you have to settle for one of these. The first one pictured is business class: black leather and looking fine. With some nice clothes, you'll be rich around the waist. Unfortunately, this version seems hard to find. I've only spotted it at a place called Le Travel Store.
The other version is easier to find. It's made by the always-reliable Eagle Creek and is canvas with the kind of buckle I used to have when I was in cub scouts. It doesn't look all that sturdy, but I haven't tested it out, so who knows. More in line with the backpacker aesthetic and with a little dirt on it, definitely a good place to hide a few Ben Franklins. You can get it at REI and a few other places, in several colors.