Topic: Komodo 4.0 IDE
Komodo has been my preferred PHP IDE for more than a year. Besides all it's nice features, I like the fact that I can run it on both my Windows laptop and Linux workstation. Komodo is Mozilla based, so 4.0 introduces extensions, just like Firefox. It's also extensible for adding your own syntax highlighting and code intelligence for your projects.
Jeff of Komodo just released code intelligence files for PunBB 1.2.14, so you can hack away and have PunBB's built in functions at your fingertips. The cix files should also work with the free Komodo Edit 4.0, just haven't had a chance to try it there yet.