I visited Spore on leisure for abt 10 days which included a 5 day cruise to Phuket/Penang and Kuala Lumpur (Star Cruises) every minute was worth it.
Its 4 hrs away from India and has a little India too. Clean, neat and good for window shopping. If you actually want to shop - Electronics should be it. Buy it and pay duty once you land in India, still cheaper than buying in India.
I travelled by taxi, expensive but comfortable with no haggling. Spend time at the Animal Kingdom - Zoo, Jurong Bird Park, Night Safari and Sentosa (one day will do justice) Mustafa is a must for all shopaholics (open 24 hrs) avoid Sat/Sun because of South Asian crowds.
Do the Singapore Flyer with the Boeing Simulator (expensive!). Overall good place for couples/families for a quick getaway.