Authentic laksa located along the stretch of Katong Road is well known over here. There are also "Katong Laksa" spread over several popular hawker centers in Singapore. Just approach any shopkeeper or taxi driver and ask for directions.
A well known chilli crab location is at East Coast Hawker Center and also at Long Beach.
As for chicken rice, try the one at Clementi Food Center Block 448 Clementi Avenue 3 called Hainanese Boneless Chicken Rice. It is just directly oppose the POSB ATM machines.
The one at Mei Ling Street hawker center Blk 159 second floor is good. Give it a try. It was formerly situated at Margaret Drive beside the POSB until the place was scheduled for redevelopment and so shifted to Mei Ling Street. There are always long queues and you may have to wait for about half an hour to about an hour for your order to arrive. It is just that good. almost 8 years ago