Some of the answers seem to be confusing netbooks with notebooks; I'm assuming you actually mean a small laptop, rather than laptops in general.
IMHO, netbooks will always be around. As I said, they're essentially small laptops, and laptops will never go away. Tablets, on the other hand, seem to rise and fall in popularity. The iPad (and other tablets, such as the Xoom) are big now because of Apple, but I predict in a few years most people will go back to netbooks or laptops. There will always be a place for tablets of course, but for most work you can't beat a proper keyboard and the ability to use it without holding onto it all the time.