All the contributers so far have missed a simple way of avoiding paying the exorbitant fees for Heathrow. Fly from Gatwick. Its easier to get there from London and much less crowded. The parking is half the price and there is a frequent bus and coach service to other parts of the country.
If you asked whoever you get your tickets from to book you through Gatwick maybe the airlines would get the message. At the moment your choices are limited by the misconseption that London's other airport is miles away.
The BAA and London Transport want to keep this a secret as this way you pay through the nose and spend a small fortune sitting on a tube train that stops at every station. Instead you could be spending 30 mins on a fast train straight into Victoria.
