I'd like to buy an argument...

That is seriously one of the best Monty Python sketches of all times!

But seriously, have you seen argument maps @ www.amap.org.uk ? It is a great tool that can help your students with lots of subjects. Here are a few examples:

Used for persuasive writing:

This one came from a student in a Social Studies class:

Technology and Bloom's Taxonomy

The University of Southern Indiana has created this awesome tool for using technology with Bloom's Taxonomy. It's pretty dang useful. Each image is hyperlinked to the tool it refers to.

http://www.usi.edu/distance/bdt.htm