Thanks for those positive comments...
I've now redesigned the site, and wanted to integrate punbb much more closely into the design. I also wanted to simplify things for users (my users are very simple...) so I have hacked around rather a lot. In fact, there's hardly any resemblance to the original punbb - and I guess that's one measure of good software - how flexible it is. Having said that, there is an awful lot of html living within many different php files - it was a bit of a challenge to find everything that I wanted to modify.
I wonder if there are any plans to separate the structure of the html from the functionality that's in the php? It would be great to have punbb tags that could be placed in your own custom design, be it a table, a div, a list or whatever. I've just gotten used to using textpattern, and it occurred to me that punbb tags, like txp tags, would make custom designs a lot easier to implement.
Anyway, thanks again for punbb.