I've flown a lot through my life - often with very valuable luggage, when making documentary films. Bits go missing only very, very rarely. I'm not saying it won't happen - it's happened to me a couple of times - but that's out of hundreds of flights. Nearly always the missing luggage is tracked and returned the following day.
Easyjet are on the whole very good (I'll be flying to Italy with them on tuesday). I really wouldn't worry.
Edited to add the thought that you could photograph your gear before you fly. That would be evidence. But I've never done that.
Edited: 19/08/2012 at 00:08