The best online trading platform in Singapore as far as I'm concerned is DBS Vickers Online. The commission charges for online trades are reasonable (I am using U.S and Singapore market as a benchmark here) and Vickers has also got some pretty extensive market data, online tools, data and research all neatly packed into its high intuitive and user friendly trading platform.
Best of all, there are no custodian charges for U.S market stockholdings - which is something all the rest of the brokerage houses and banks charge.
Nuff said. Find out more or visit their branch at Level 2, PWC building at Cross Street to open an online trading account.