Developing multiple charts with same look and feel - patterns?

Question

I'm on a team that will use the Microsoft .NET Chart control, and want to build something that will allow us to plug in data and render the chart as a PNG. This will be saved to a binary HTTP stream (we won't be using the built-in Charting HTTP handler).

I don't want to hide any of the advanced features (since there will inevitably be a chart that needs to do unusual things), but I do want to provide some "defaults" and "helper" functions that will:

1. format the chart
2. accommodate common types of data (time series by month, "top 5", etc.)
3. provide SOME encapsulation: i.e. DateTime objects will be rendered according to some predefined formats: "YYYYMM" or "MMM YY"

Is there a pattern that will help?