I need to create a web application that displays a Gantt Chart (resource- and task-oriented views). It will display the chart based on some data and the user should be able to change the data via the GUI (scheduling new tasks/resources, rescheduling, adding sub-tasks, etc..).

What is the best technology for me to use? I've been looking at ASP.NET and Silverlight, and Silverlight looks like it might be easiest, since it has some charting controls, but they are relatively new... Does anyone have any suggestions? Would Silverlight be the best solution?