I travel in some fairly uncertain places at times, and I always like to know where my most critical stuff is. That's why I rely on a leg wallet (got this one for SGD$20 in Singapore).
I carry multiple currencies (about $20-$50 worth of nine different ones, last time I counted) and a few hundred USD$ plus my passport, Green card, spare credit card, medical card and so on. I wear it all the time, except when showering, and I get a few odd looks from people if I have shorts on, but I always feel secure. I used a pair of scissors to taper the Velcro ends - as if you don't align them, they can irritate after more than 24hours on a plane or traveling.
Another tip: a few years back, I had to leave my laptop bag in a dodgy hotelroom in Guadalajara, where someone had already tried to get in while I was snoozing. I just hung the entire bag by its strap behind the curtains, up against the wall, but with the curtains open. If you didn't look for it: you wouldn't know it was there.