One of our LEGO® MINDSTORMS® enthusiasts, Laurens Valk, has made this fantastic article which gives a very good overview of the different NXT sets.
Tutorial: Understanding the difference between NXT set versions
Do you sometimes get confused about what the differences are between the different NXT sets? And would you like to know how to upgrade the software from the NXT 1.0 to the NXT2.0, and where to buy spare parts for your NXT kit? Then keep reading and Laurens will take you through all the steps and give you tips to further reading. ENJOY!