IME you'll make friends via your work rather than via where you live.
Though that said if you have a condo
and pool areas you might meet some people there.
You can section SG off into lifestyle layers if you like.
- bachelor pad down in the CBD/riverside
- place in expatville (River Valley, Holland Village, Novena etc)
- almost suburban, Toa Payoh, Ang Mo Kio, east coast and so on...
- the wilds (anywhere apart from above).
What do you want? To be right in the buzz, or occasionally feel like there is down=time...