Which Pyhton Modules?

Hi, I was just wondering which external or extra Python Modules do people find the most nessecary, functional or useful?
PyGame seems high on the list, I have also used PIL (Python Image Library). I know there are many more. It would be a good to see what people use or which people can’t do without.
Also some of the uses, dependencies in Blender of the extra modules.

Thanks. M.A.

Sorry for bad Typo.

I try to use only blender modules where possible, - pygame seems seperate to anything youd do in blender, Im sure it could be used but since pygame uses its own window it would not intergrate well.

possibly numarray?