Thought I'd give you a bit of an insight into what sort of tools I use and recommend in day-to-day work.

• Coding: Crimson Editor is my main coding application. I use it for all text-based development (HTML, CSS, PHP, etc). It isn't the most feature packed program, but it has a very good mix of features and feels nice. There are a few features I would -love- to see, but unfortunately it isn't being updated anymore. I will probably end up moving accross to Zend Studio soon, although one thing that really annoyed me last time I used it was the open file tabs aligned to the bottom of the screen.
  
  
• Database Management: PremiumSoft Navicat is an extremely powerful piece of software for managing databases (mySQL in particular). Many people use web-based management tools for this sort of thing, but once you use an application like this, you'll find your life a LOT easier when dealing with databases, I guarantee it! It can import any number of formats (including excel) and just having the application sitting there really makes it convenient. Any serious developer should be using something like this.
  
  
• Firefox and Add-ons: I use firefox as my browser, and there are several very useful tools you can install to assist you with web development. The webdeveloper toolbar provides some outstanding tools for troubleshooting and testing, a must have. Livehttpheaders can show exactly what is happening, as it happens, useful for debugging weird issues. Screengrab! is great for easily generating full length screen grabs of websites for examples/printing, etc.
  
  
• Some of the less exciting but very essential applications are... filezilla for FTP, winSCP for secure file transfers, and putty for ssh'ing to servers.

Feel free to add any other essential development tools that should be on that list!