If you like drawing UI sketches on paper and plan to design iPad applications, there is a sketchbook for it - http://www.ipadsketchbook.com/

Sketchbook sheets have the layout of iPad in actual size printed on the front. iPad screen is covered with grid which allows to lay out interface elements conveniently. On the back sheets are just covered with simple square grid for comments, various thoughts, design of individual elements, etc.

Technical specs (better than iPad in many aspects):

  • 42 A4 sheets
  • actual size of iPad
  • convenient grid
  • multitasking support
  • zero-watt consumption