NoteLab was designed for my needs for mathematical note taking. However, it can be used for any note taking.  Here are some of its biggest features:

• is freely available under the GNU GPL
  
  
• runs on Linux, Windows, Mac OS X, and Solaris


• saves notes as a SVG (Scalable Vector Graphics) images, an open industry standard. As such, any SVG reader, not just NoteLab, can be used to view saved notes.


• can export notes to a rastered or vectored image (the PNG, JPEG, BMP, SVG, SVGZ, and many other formats are supported)
  
  
• has a graphical preferences manager used to specify your pen and paper preferences
  
  
• has a graphical memory manager that allows you to specify the amount of system memory NoteLab is allowed to use
  
  
• smooths strokes in real time as they are written
  
  
• supports printing of notes


• uses a abstracted rendering system. That is, if notes are exported to an image or printed, they look exactly as they appear on the screen
  
  
• allows any part of the notes to be resized, moved, deleted, and have their line width and color changed at any time. NoteLab sees a page as a collection of strokes that can be manipulated, not as a grid of colored regions, like some paint programs


• uses screen rendering optimizations to allow for responsive note taking


• uses custom designed graphical elements specifically designed for tablet PCs


• supports wide rule, college rule, and graph paper with customizable paper color


• supports command line switches that allow for the customization of NoteLab at startup


• supports zooming of notes such that notes don't become "pixelated" as one zooms in. Curves drawn on the page look smooth at any zoom level


• uses custom icons
  
  
• supports cutting, copying, and pasting of strokes