MaxVal, an IP research and services firm, offers a suite of useful (and free) patent tools. The graphical patent family tree generator is especially nice. The USPTO widget is also useful for compiling data about a specific patent from various USPTO databases.
I'm the librarian for research services in the Engineering and Science Library at Queen's University in Kingston, Ontario. I've been working with patent information since 1991, including seven years at the U.S. Patent and Trademark Office. I believe that the dissemination of patent information is a public good and should be promoted, especially in the education of science and engineering students.