This may be apparent by now that web design is not graphics in a page or the colour of the background of the webpage. It has gone well beyond that and for the same reason web designers are attracted towards an IDE (Integrated development environment) that would be best suited for this need. Previously the WYSIWYG kind of IDEs were a thing to look for. But currently it is the web standards, clean code and ease of use is what everyone looks for. Fortunately we are not limited to Notepad in windows or TextEdit on MAC.
One such IDE is APTANA Studio. This is based on the opensource Eclipse IDE. Current version of the IDE is much better than its previous versions and now it comes with project templates for HTML5 applications. There are project templates which are already installed with the IDE itself. There is an option to choose the template to use in your project, and if you are connected to internet then there are options for a template to be downloaded from the source control systems like github. This makes a perfect case for people who are just beginning to use Git or not used to it. That means whenever you create a project with these kind of templates, you are bound to get the latest one form the repository. So you will get the benefit of the awesome developer and designer community, who is constantly contributing to the original source code. And one does not need to know the inside working of the system. Thats a huge plus point.
Well, by this time you must have sensed that Git support is inbuilt with the IDE. So one can always see if the changes are committed or not. That way it will make your code constantly tracked by version control systems. There is a built in terminal(command prompt) inside the IDE. So one dose not need to open it separately to work in a command prompt.
Next is its look and feel and working in different operating systems and this IDE simply the same IDE in Windows and Mac operating systems (I have not tried the Linux version yet).
This supports a lot of languages starting from HTML, Javascript, CSS, PHP, Ruby and Rails. While writing my own CSS and javascript the code hinting and responsiveness of the IDE just blown me away. Its just those simple features, which, if one gets used to, then there would be no coming back to a bare-bone IDE like Notepad or TextEdit. While editing CSS, and adding a colour value, there is a little display as to which colour this value is representing! Thats just too good. There is a web previewer inside the IDE itself, if one needs to test the design one need not leave the IDE too.
Overall in my opinion this is one of the IDEs to get used to if one is doing web design in current age.