Learned about this new site from Tomorrow.SG, and I found that GoThere.sg is really helpful for both motorists and commuters in Singapore. Not only that we can search for any addresses in Singapore, we can also easily put two addresses in Singapore and the site will automatically calculate the best route from point A to point B under three main categories: "Train + Bus", "Bus" and "Drive".
Its map is powered by Google and the recommended route will be marked on the map. And the best thing I find on this site is that we can easily drag the point A and/or the point B markers to anywhere within the map and the route -- be it driving route or public transport route -- will automatically be recalculated. Estimation time for each leg of the route (bus, train and even the walking time) is given. For driving routes, option to avoid ERP gantries is also given. Searching can be done by entering the partial address, building name or the postal code.
For me, this site is currently the best replacement for the Street Directory site, which is still offline until don't know when.