The Heathrow Hilton is way overpriced for what it is. If you want to stay at the airport, Marriott and Sheratomn Skyline are relatively cheap and good. The Le Meridien or the Radisson are a bit more upscale and have decent prices at times.

The biggest problem with Heathrow airports is that the food selection sucks and unless you havea car you are stuck in the hotel restaurant.

If you want to stay in a Hilton and have the time, take the Heathrow Express out to Paddington and stay at the Metropole. Nice mid-eastern restaurants on Edgware road. The commute to Heathrow from Metropole is 50 minutes max.