Pulau Ubin island is just located on the other side of Changi Beach and can be reached by boat from the nearby Changi jetty. This is a very interesting and beautiful island, and more information is at my Pulau Ubin VT page.
Near to the Changi Beach is a bridge across the Changi River. You can get a nice view of the fishing boats as well as the Changi boat jetty here.
Actually, you can get a glimpse of Changi Airport and its control tower at the Changi Beach as both are located very near to each other.