American Express and ebookers are offering a £50 discount on any five night holiday booked with an American Express card.
The details are here (click on Travel then ebookers). (EDIT: deleted as deal now dead)
You need to book by 31st March for a holiday before 31st December, and book a flight AND 5 nights in a hotel.
(There is another version of this promotion if you only want a 4-night hotel stay – the code TRAVEL50 gives you £50 off if you book by 10th February for travel by 31st August.)
ebookers, amusingly, has a credit card fee! Part of your £50 discount will therefore be eaten up by the additional charge for using your Amex card over a debit card. I’m not sure what happens if you use the Amex code and then pay with a debit card – I assume you would still be OK.