Another credit card to consider is the newish "travel" credit card. See Travel Card for full info.

You get 1p for every pound you spend. The money accumulated can only be spent at the Coop Travelcare shops, where it can be used to be flights, holidays etc.

I just got a fare LHR to JFK on UA for £200, all paid for by the money accumulated. Better still, I will also earn UAL mileage on this flight and hence get another 8000 or so miles.

There are some additional travel insurance benefits with the card, but nothing particularly special.