It's important to keep your cash tucked away when you travel. You should assume that there is always someone around wanting to separate you from your money. After all, people even get pickpocketed in the Vatican on a regular basis.
Many money belts and pouches out there are suited better to backpackers and adventure travelers though than to someone trying to do business abroad. I take the Eagle Creek All Terrain money belt I reviewed earlier with me on almost every trip and like it, but it requires dressing down, not up.
The leather belt from the National Geographic Store pictured here is a different story. You'll have to cough up $48 for it (click the picture to check it out), but it'll work with a pair of dress pants or a pair of jeans equally well. Magellan's sells a similar leather money belt for around $30, with both coming in black or brown and a range of sizes. The descriptions say you can stuff $1,500 in one of these, but I'm not sure why anyone would need to carry that much cash around and if you only put in one layer of bills they hold 5 hundreds.
I also like these money socks because it takes the old idea of hiding money in your shoe and makes it simpler and cleaner. You have to buy these in sets of three for $30, and they're really nothing special in terms of the socks themselves, but an extra layer of protection. There's a zippered pouch at the top of the sock and it's big enough to hold your credit card(s) as well. Alas, you'd better have normal feet: one size fits all. These also require being in a place where you're going to wear pants all the time, so no dresses/flats or shorts and flip-flops.