Thank you all for your valuable input. I think ultimately we will need to come and look at the various areas (and what is available for how much in each) before we will really know what we want to go for -- but this helps with a shortlist of areas to explore.
It sounds like West Kowloon/Olympic (Florient Rise, Island Harvourview, Park Avenue and maybe One Silversea etc) are worth exploring for the newbuild, facilities, good commute and lower rents -- but we should watch out for what it's like for pushchair access and being connected to street life.
The more traditional expat districts of Happy Valley, Mid-levels etc also sound worth exploring, but we probably won't get much for our money (the suggestions for which roads in Mid-levels to look at are valuable though).
I think Park Island we will park for now -- maybe something to consider along with Discover Bay once we've spent a year living somewhere more central if we then decide to move further out for a bit more space.
A general question -- there was some discussion of property prices -- are prices still rising rapidly in HK, and what is the feeling for what the outlook is like? Reading the international papers from the UK, you see quite a bit of discussion of whether China's property bubble is going to burst (and what impact that might have on the Chinese economy), but don't see anything specifically on HK, which I imagine is a distinct market. Any thoughts?