I have stayed at the Regent Cha-Am several times. The first being some 20 years ago when it was the only hotel on that particular stretch of beach, up to 2 years ago.
The standard rooms are clean and comfortable, but avoid getting one overlooking the gardens as the birds are incredibly noisy in the afternoons and early evenings. There are also rooms overlooking the car park, which should be avoided. The best rooms look over the pool.
There is no point in opting for half board or bed and breakfast. The hotel food is very expensive, and not very authentic. A better option would be to visit Nee's Restaurant for breakfast (and the occasional evening meal). If you come out of the hotel and walk left, her restaurant is the first you will find, about 400 meters away. A good breakfast will cost about 70 Baht (£1).
On the way to Nee's you will undoubtedly meet some taxi drivers. These guys will be more than happy to advise you on excursions .don't forget to haggle on the price!
Drinks in the hotel are an arm and a leg, compared to bars outside"¦"¦avoid!
The beach outside the hotel is not particularly pleasant. It is generally not used for sunbathing, but this is unimportant as the hotel has a very nice (and big) pool. On the beach there are plenty of places to eat, have a Thai massage (for 150 Baht the hotel charges 600!), or to buy fake designer clothes.
If you get the urge to have a drink while lying round the pool, walk twenty yards to the left (while facing the sea) to the small bar adjacent to the hotel, and buy your drinks at a third of the price.
Outside the hotel there are plenty of tailors who will be willing to knock you up some clothes. I have found that the best thing to do is take one or two items that fit you well and let the tailors copy them in the fabric of your choice.
There is also an optician where you can get very cheap prescription glasses made.
You friendly taxi driver will take you the 15 minutes to Hua-Hin, and pick you up at a time that suits you rather than rely on the hotel mini bus.
There are some very good sea food restaurants overlooking the harbor, and some very poor ones elsewhere. Either take advice from you taxi driver where best to eat, or find somewhere that is busy with locals.
The market is a permanent feature of Hua-Hin, but if you are looking for dodgy watches, they are few and far between nowadays (compared with 10 years ago). A good starting point when haggling for anything is a third of the price asked.
Have a good holiday, and post back if you would like further info.