We went to this restaurant a while ago: Baan Khanitha.
Price: Given the food selections in this city, and that we're talking about Thai food, the native cuisine, the price is definitely on the expensive side, given the other options in the area. Excluding alcohol, our dinner came up to be just under US$30 per person. We ate family style, sorta.
Ambiance: Definitely reflected in the price range. Jeans, shorts are frowned upon. White table clothed tables, hushed speaking. The restaurant was fairly empty the evening we went. The rooms were well lit, furnished with wooden furniture, and decorated with sparse artwork.
Service: Waiters standing by attentive to your needs, without your having to ask. Despite their attentive presence, they kept themselves low pressure. They spoke decent English... but the menu is written in both English and Thai so if in doubt, just point.
Food: Don't think I forgot the most important part. The food was excellent. Range of choice vary to traditional pad thai to iterations of all sorts of meats, vegetables, fruits, and spices. Portion sizes for the entreee dishes are small, unless you ordered a noodle dish. Rice is served separately, and usually in a big basket container, with the server serving a portion on your dinner plate.
In short, you get what you pay for in this place. It's probably too pricey for regular visits, but if you're trying to impress someone, this would be a good place to start. And guess where I'm taking my parents when they show up next month.