I am in Hua Hin now -- my fifth visit here in the past few years.
Any of those resorts suggested above by Kettering Northants QC would be 5-star.
The locals tell me that Chiva Som is 7-star, but I have no first-hand experience.

I will say again, Hua Hin is the best choice for Colin's OP request for, "the best luxury beach resort that is driveable from Bangkok airport."

Weather here now is magnificent: tropical balmy, but not hot and not humid.
This evening has the soft, warm, air that is very soothing.
It provided the perfect atmosphere for our seafood dinner on a deck overlooking the Gulf of Thailand (complete with candle light).

November is "shoulder" season here, so no crowds at all.
Most visitors are middle-age Europeans; including a few families with children.
Hua Hin is popular with Scandinavians and Germans, based on the restaurants I see and the languages I hear.

Hua Hin is the second most expensive resort in Thailand --after Phuket -- so it attracts visitors who are able to afford higher quality accomodations and service.
While there are a few guest houses here, Hua Hin is really not oriented to budget travellers/backpackers.

If any specific questions, you are welcome to send me email or private message.

- Peter
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