Free tools supporting panning / zooming:
Live Charts
DynamicDataDisplay - a nice, open source data visualization library. Unfortunately it's not been updated since April 30, 2009.
OxyPlot
Free tools without built in pan / zoom support:
WPF Toolkit. Supports most important 2D charts, you'll have to implement pan / zoom yourself.
WPF Toolkit Development Release. Supports stacked charts, equivalent to the Silverlight version.
Paid tools with built in pan / zoom support:
Visiblox Charts. Support for the most important 2D charts, comes with zooming and panning. The free version comes with watermark. (See this blog post on using zooming / panning)
SciChart. Supports most important 2D charts, comes with zooming and panning, mouse-wheel with animation on zoom. (See this blog post on using zooming / panning across multiple charts)
Infragistics xamDataChart. Supports most important 2D charts, zooming and panning. See this blog article on how to use zooming.
Telerik RadChart. Supports lots of 2D charts, has some support for zooming and panning, you might need to do a little work on that.
Visifire. Supports lots of 2D charts and zooming without animation, might need to do some extra work for smoother zooming.(This service is no longer available)
DevExpress ChartControl. Supports most common 2D Series types, zooming and panning (scrolling) operations can be performed using the mouse, keyboard, and touch gestures.
Syncfusion SfChart. Supports many 2D series types and provides the interactive zoomingfeature that supports the touch mode. Various zoom types are supported (mouse wheel, pinch, selection).
