I don't understand those here arguing in the airlines' favour. Nor do I understand the glib comments along the line of 'I'd be quite happy to be delayed for a payment of x Euros'.
Here's my story: BA delayed a flight from London to Athens in August by nearly 5 hours due to an aircraft malfunction. Another 767 was not available, nor was there room on any other flight.
I had a connection (to a ferry from Piraeus) with around 5 hours leeway [so it wasn't as though I had not factored in potential delays].
I had to stay overnight in Athens (which was mostly covered by insurance so I was not greatly out-of-pocket).
So, for what would BA be compensating me? The loss of a whole day of my holiday. Instead I had hours hanging around Heathrow, unnecessary journeys in Athens and the hassle of booking replacement ferry tickets. I think that deserves some recompense and I have already been in contact with BA today to press my case.