score:10
Singapore has three mobile phone operators and given the small size of the country, their coverage is fairly similar. Their offerings aren't very differentiated for contract plans, but for pre-pay plans there are some differences.
All you need to get a pre-pay SIM is your passport and then you can buy the SIM cards from any convenience store, or a company-specific mobile phone shop. I also wrote about getting Internet access in Singapore on my blog - it's a bit out-of-date but may be helpful nevertheless.