Short review: Lilliput USB monitor
Small and expensive but totally worth it if you need a third screen for your laptop.
If you are only using one monitor and satisfied with it there are bigger and better monitors to have for less money. But if you, as me, only have a dual head video card and already two monitors the lilliput makes the day.
I have it for keeping an eye on email or chat or spotify or logs or perfmon or whatever needs little space at the side of my main monitor.
Easy installation in Win7 and it pops up as an ordinary video card. No pesky dialogs floating around.