Whenever I fly, I secure the bag with a cable tie. That way security can look inside if they want, but a light fingered grunt will probably go for something easier.
When it gets to baggage collection time, it's obvious if anyone has been in my bag or not, and I can check the contents.
So far that technique has proved safe from Stansted and/or Spanish handlers (who have twice helped themselves to odds and sods - pair of shorts and a Swiss army knife - I know, weird eh!).
All my expensive stuff always goes hand luggage anyway, have you not seen how they throw the hold luggage about?!! What the iPad owner was thinking when he put his animated tea-tray into hold luggage is beyond me!