This is tutorial is tailored specifically to people who will have to permanently let go of their PC before they can import the data into their Mac, thus relying on an external hard drive. This happened to my father in law (suegro) who was exchanging his PC for a Mac in a store, and could not wait for them to do the data transfer themselves.
For cases like these, I add some steps as fail-safes, but as the data in your PC will never be available to you again, better be safe than sorry. It's not hard, and all you will need is an external hard drive (HDD) and diligence.
1. YOUR SOFTWARE
In your PC, go to Control Panel / Programs / Uninstall. This will give you a list of all of the software installed. Skip the ones that come included with Windows and write down which ones you plan to use, as you will that way know which to install when you get your Mac. In this case, we retained Itunes, MS Office (including Outlook), Skype, Picasa, Google Chrome, Blackberry Desktop, and Kaspersky Antivirus.