I would say Emerald Hill area. You could rent one of those lovely converted conservation (historically preserved) shophouses (like townhouses) but these usually have no facilities (pool, etc). Alternatively, if you're for
condominium living, you could consider Hullet Court, which is also located within the Emerald Hill area. Location is fabulous, walking distance to orchard road, which is the Oxford Street/Regent St of Singapore and there is a tube station within walking distance (Somerset MRT station). Warning: It comes with a price as rents are quite high.
Alternatively, there is another pocket of these converted conservation houses at Blair Road/ Spottiswoode Park Road but this is closer to Chinatown, and not as central as Emerald Hill Road.
Or if you're looking for a more bohemian lifestyle community to live in, you could consider the Holland Village area, but again, nowhere as central as Emerald Hill Road.
You can check out Emerald Hill Road and other similar conservation townhouses (some come with jacuzzi, rooftop gardens, etc.) for rent.
Hope you find the information helpful.