Need a 3rd display on your laptop?  Everyone says Matrox.  I say no!

http://sewelldirect.com/USB-to-DVI-External-Video-Card-High-Resolution.asp

These are apparently just DisplayLink adapters, which are available on MonoPrice for cheaper and with different features such as audio output.

http://www.monoprice.com/products/search.asp?keyword=usb+display+adapter&x=0&y=0