Super 2d/3d Graph Library is probably the best .NET charting solution for most .NET developers:

• Royalty-free (no distribution costs)
• More than 45 different chart styles (2D, 3D, XYZ, Combo, Gauge, Gantt, Radar, ...)
• Formula plotting in 3D (scatter, lines, mesh, surface)
• Surface chart from random XYZ points (uses Delaunay triangulation algorithm)  New!
• Support for PDF format (also useful for printing charts)
• Support for SVG (Scalable Vector Format) format
• Support for standard bitmap formats (PNG, TIFF, BMP, GIF and JPG)
• Support for high quality animated GIF on-the-fly creation
• Very easy to use and deploy - Only one assembly file (1 dll)
• Same component for ASP.NET and WinForms applications
• Well documented - online tutorials and 174 page developer reference
• ClearType support and automatic antialiasing
• Custom chart resolution (eg. 300 dpi - great for printing in high quality)
• Additional calculations (average, pareto, maximum, max/min values, trend lines, ...)
• Full featured context menu
• Customize any aspect of the chart (font, texts, alignment, colors, fills, ...)
• Source code option available
• ... and many more great features! (go to Features page for more information)