Although the Marina Bay Sands is the famous hotel in Singapore, I recommend the hotels along the opposite shore if you want to see the night views.

I was staying at a room without the canal view of the Marina Bay Sands. However, this hotel has a window in the elevator hall where you can enjoy a night view of the Marina Bay Sands. By making use of this glass window, I was able to enjoy the views of both directions.

Room keys are required to use the hotel elevators. You can only get off on the floor that your room is on, so guests staying at the lower floors cannot enjoy the night view.