Hi newbienz,
Given the information you have provided, it sounds like Churton Park or maybe Woodridge in Wellington would be the perfect suburbs for you! Churton Park has plenty of homes in the 600-700k price range (and above!), many of them will even be 4 bedrooms! It has modern homes, many of them built in the last 10 years, and has a reliable bus service to and from the Wellington CBD at all times of the day. There are plenty of people from Asia there, in particular India and China, and the income bracket of the area is certainly in the higher end! It is a modern, affluent area; seems to tick all of the boxes you suggested
Woodridge is very similar, although the bus network only runs in the mornings to the Wellington CBD and in the afternoons from the Wellington CBD, which shouldn't be a problem with normal IT hours in Wellington. Very much the same as Churton Park otherwise, except Churton Park has a shopping area, is closer to Johnsonville and SH1, and just generally outclasses it.
Whitby is very nice, and has a large variety of homes from different years.... There are certainly some nice modern homes (<10years old) within your budget, not to mention a similarly high socio-economic status to the aforementioned suburbs. There isn't a direct bus from Whitby to Wellington CBD as far as I know, but you could get a bus to Porirua or Paremata train stations and bus/train from there into Wellington in the mornings and back home in the evenings. Aotea in Porirua is also nice, modern and within your budget; however similarly, there isn't a bus from Aotea into Wellington.
I'd overall highly recommend Churton Park based on what you have provided
If you have any other questions, feel free to ask. We're happy to help,
Ansistent