On top of the resources that you listed, I have found these two sites to be incredibly useful:

1. [peeron.com][1] - Large set database and instruction scan library
2. [bricklink.com][2] - Lego marketplace selling millions of used and new parts and sets. This is also a nice reference for information and inventories related to old sets.

It's not a site, but if you don't mind books, I would recommend [The Cult of Lego][3] by John Baichtal.

You also might be interested in finding a LUG (Lego users group) near you. Here's a [map][4].


  [1]: http://peeron.com
  [2]: http://bricklink.com
  [3]: http://www.amazon.com/Cult-LEGO-John-Baichtal/dp/1593273916
  [4]: http://www.lugnet.com/map/