A work in progress- The development environment is one of the first key elements that is required to do anything with Drupal or web development in general, your work needs a place to live. This series will cover a variety of development environments that are suited to Site Builders, Themers, and anyone getting started to Drupal. They range from the super simple to fairly advanced, so there should be something for everyone and no need to be intimidated.
Pantheon is a hosted Drupal development enviroment and hosting service. It is considerably more advanced than Drupal Gardens, yet still fairly easy to get going with. The service offers two free development sites to start with. You only pay when you launch, and add your own domain.
While there are a variety of virtual machine applications available for desktop use, VirtualBox has been rising to the top. It is easy to install, easy to use, and free helps. There are a variety of applications like Vagrant that also can be used to extend VirtualBox as well. VirtualBox also has great support for emulating extra features of the desktop, like USB and even multiple displays.
Dev Desktop is provided by Acquia, and is probably the most direct and easiest way to get started locally. Dev Desktop is a self contained download that includes an entire AMP stack for both Windows and Mac. Linux is not supported. Dev Desktop would be a good solution for those that have never installed an AMP stack and/or are still on the fence deciding if Drupal is for them. This is because the AMP stack is specifically tailored to Drupal, and even includes an install of Drupal ready to go.
Drupal Gardens is a software as a service (Saas) offering from Acquia. There is nothing to install, simply create an account, login and begin creating a Drupal site. Drupal Gardens offers an almost zero degree entry point and is ideal for those evaluating Drupal, you can jump in and get a feel for Drupal immediately, without any concern or effort of setting up a LAMP stack, or maintaining a system. It also means you may use what ever local enviroment/OS you want.