Bradders: Parahandy and I live quite comfortably on about 30,000 baht a month. We don't skimp on food or drink, but we don't frequent the bars or restaurants in Hua Hin. We eat at home because P. loves to cook, but we may have the occasional lunch in Hua Hin when we're shopping.
We have the benefit of living way out of town and the cost of living is considerably cheaper (we pay 2,000 baht a month to rent a perfectly decent house with a large garden).
If you're going to live in or close to Hua Hin, then I guess about 50,000 baht a month should suffice. It depends how much company you need in the evenings...
VS