Smashing Magazine have come through here with a superb article about free and purchasable tools to help you code in PHP. Rather than witter on about code completion and so on, they actually show you what these things are, allowing someone who's never used an IDE to have an impassioned response.
Pete, you might want to check this one out. I know you do some PHP coding and these tools can really help!
I'm probably going to get Netbeans running on the laptop as it seems to have everything you might need. Especially useful for bug hunting in Chom 3.