Red Arrows
I can understand why people question the cost-effectiveness of the Reds given the current climate, but surely since 1980 (when they began displaying the Hawk) they have not only helped put the RAF in peoples minds all over the world, but done something for UK industry too.
Look at all the nations flying the Hawk around the world, and see how many were visited by the Reds before they bought Hawks. As well as it being an excellent aircraft in its own right, obviously.
Keep them at it and give them a Reserve number plate too.