When I saw these bamboo iPad holders at IKEA I couldn't put them in my cart fast enough.  I have one on my painting desk and one in my kitchen.  Sometimes I paint from reference photos on my iPad.  What is great is it doesn't take up as much space on my desk as a computer monitor would, and you can zoom in and out quickly and easily.

This is a work in progress painting I did plein air at Animal kingdom a few weeks ago and now I'm tweaking it a bit just to punch up the value.