ETFs are really the way to go if you want to invest in an extremely flexible, transparent and cost efficient manner. They trade like shares on the stock market but are more diversified in nature like unit trusts.
Most fund managers that managed unit trust funds rarely manage to outperform the benchmark index. So in that case, why not just purchase the same components in that index. Hence the slow raging popularity of ETFs.
The enjoy high liquidity just like stocks, with low cost (low management fees and no sales charge - only brokerage commission). And there is typically an ETF for every index available in the market.
Some prime examples include the SPDRS Trust Series 1 (Ticker: SPDR) that trades in the U.S market. This ETF tracks the S&P 500 and holds the same component stocks in their respective quantums. Closer to home, there's the STI ETF (Ticker: ES3.SI) that tracks the STI Index.
Investing in ETFs is as simple as purchasing a stock and you can do it quickly and rather cheaply via online trading.
Click for more details on ETFs listed on SGX.