recommended general-purpose string template packages?

[John Machin]

Hi,

In general, I'm mainly interested in a template engine for dynamic web
pages but would like a general purpose one to avoid learning yet
another package for generating e-mail messages, form letters, source
code, whatever.

In particular, does anyone have much experience with the Python
interface to Terence Parr's StringTemplate
(http://www.stringtemplate.org/)? Reading the website, I'm attracted by
the approach, but a Google search (both generally and in this
newsgroup) gives me the impression that it's little used in the Python
world.

TIA,
John