Singapore is an amazing city - worth the stopover, or even stay for a few days. I stayed for 4 nights, and I was constantly amazed. It's a beautiful city, although it can be expensive but if you're money-smart, you'll be able to do Singapore on a budget. Public transport here is amazing - no need to hire a car nor a taxi when you're visiting. It's a safe city - you won't feel out of sorts when you're here.
Insider Tip:Get the ferry from Clarke Quay, and cruise around Singapore. Fantastic sights and photography opportunities. It can get quite humid, and tends to rain at times every day, so be sure to have an umbrella or raincoat on you at all times - you don't want to get soaked wet when you're expecting it the least!