Web developer tools I use every day

In my work as a PHP/Javascript developer there are a few software tools I use every day to assist in productivity and implementing effective code. The majority of the tools here are Open Source and many are available for Windows users as well.

Operating System
For most of my work I'm using a computer running Ubuntu which is a popular and stable version of Linux. There are plenty of other flavours but I like this one as it is easy to manage. There is a huge range of software in the repository (catalogue) to customise your installation. And as it's Open Source you don't have to pay any licence fees, though I'd encourage you to contribute something.

Integrated Development Environment - IDE
The IDE is the core of the developer's toolbox and will have different features/plugins depending on the programming language or languages you work in. This is where you do most of your programming so you'll find most IDE's to be very customizable.

I use Netbeans which provides a very good range of tools such as debuggers, code completion, repository integration,  plugins for different development tasks (eg. Firefox extensions) and much more. I have also used Eclipse in the past and this is also a very good IDE.

UI Design
This is so often done with scraps of paper or Excel spreadsheets, Powerpoint or Photoshop if you are a designer.

I now use Balsamiq Mockups [review] as it provides a very simple to use interface with a hand drawn style to the images. The files can be shared or the exported images used in presentations.

Managing Ideas
Nothing beats a day book for jotting things down as you research an issue but if I need an electronic record then I'll use Freemind. This is a brilliant piece of software which allows you to jot down ideas quickly and simply. Mind Mapping tools like Freemind are really handy when making sense of requirements or when problem solving.

Documentation
We use a Mediawiki installation on the LAN for most documentation. For shared items such as task lists we have been using Google Docs for the past couple of years. This works very well as the task list is in spreadsheet form.


Debugging
For Javascript the obvious one is Firebug on Firefox and I believe there is now a 'lite' version for Internet explorer. Venkmann is also another established debugging tool for Javascript.

For PHP debugging work I use xDebug which is a PHP Module and can also be linked to KCachegrind to provide awesome, graphing of the code activity.

File Management
I can't do anything without FileZilla which is a brilliant Open Source FTP client from Mozilla. Invaluable for uploading and downloading files from the webservers I manage.

That covers the main day to day tools I use and I discover new ones occasionally which I'll share when I find them.

Everybody has their own favourites and teams often tend to share a set of tools. What are your favourites?