Please do not post here that you are having the problem, its established that a number of people are experiencing it and there are other threads on the topic.
My solution to the problem was as follows:
Exit the Launcher (if still open).
Go into Program Files--World of Warcraft and delete the WTF and Cache folders.
Move your Interface file to the Desktop.
Disable your Anti-virus (in my case Avast!).
Disable your Firewall (Windows).
Restart the launcher.
After this the download still moved incredibly slow...approximately 1% every 5-7 minutes until it hit the 10% mark then it immediately shot to complete and began the actual patch (which was done in less than 5 minutes).
Hope this helps some of you.