Simple solution - keep valuables in your hand luggage!
I took a laptop to the Dam last year, and kept it in my hand luggage; not only can things get robbed but they throw cases around like they are balloons and things are liable to be broken.
I also keep phones, money, passport, wallet etc in my coat when travelling, can't understand these people who keep valuable things like their wallets, money and passport's in their cases, they are leaving themselves wide open to theft; and I wouldnt like to be stranded in a foreign country with no money/wallet and no passport to get home!
Not only does it leave you open to theft, but it also means that should the luggage go missing (and it often does) for whatever reason, you have none of these vital possession's when you arrive!
Gutted you lost ya stuff mate, but im asure you will learn from this and never make the same mistake.
Padlocks are all well and good, but if a baggage handler wants to get it off, he/she will, and you have no way of proving it was padlocked unless you specifically request at check in for a receipt to acknowledge this fact; not that it helps you if things do get stolen, but it helps you make a claim if they do.