Yep Fisherman V is nice. Often go there after late work to enjoy
the breeze and booze. Bring a partner if ya want to coz lotsa dark
spots around when ya walk.
Changi Beach is also great but ya gotta bring your own
drinks.
If ya like to see more crowd, East coast can be a good place. Both
ends of EC are the lovers' corners 
If fuel is not a problem, try driving on the northern highways, it
can be very relaxing too.
I'm not too sure of the west coz I stayed East
