Something I've been playing with in the past week or so has been a product called Microsoft WebMatrix - a free web development tool from, you guessed it, Microsoft. It includes everything you need to put together a complete web site - including a Web server, database, and programming frameworks.
When you start the program up, you get four options - open previous WebMatrix sites (My Sites), Site From Web Galley, Site From Template, and Site From Folder. A Web Gallery site allows you to seamlessly connect to popular and free open-source Web applications such as WordPress and Joomla. WebMatrix goes through the process of downloading, installing, and configuring everything for you. There are also 5 templates to choose from - Empty Site, Starter Site, Bakery, Photo Gallery, and Calendar.
Upon opening a web site, you can go straight to writing code or manage the settings of your web site - enable SSL, select the .NET Framework, enabled PHP, etc. The file editor is your typical editor with line numbers, syntax highlighting, and code completion. You can also create multiple different files from within WebMatrix - including HTML, ASPX, CSS, and JavaScript files.
When you are finished editing, you can click the run button on the ribbon to view the results in your selected browser.
I'm still playing with the product to learn its ins and outs, but it seems like a pretty good starter development kit. Check it out for yourself at http://www.microsoft.com/web/webmatrix/.