Welcome, Chris.
I only signed up to comment on this article.
You guys should stop giving advice on mobile data security.
Android and windows phone 7 have very insecure ways of factory resetting and a standard factory reset is not enough if you value what was on the device.
Please stop putting out such rubbish that a standard factory reset is enough when anyone working in IT security will tell you this is not the case and is very inaccurate information.
Rant over!
I think you address an important point... IT security professionals would have more knowledge and tools available to them for recovering data, definitely.
It is somewhat hard as to where to draw the line. If you are handing your phone over to your 5 year old niece Sally for an mp3 player and offline box a factory reset is more than adequate. If you are expecting a Government seizure and forensic examination of your device a factory reset is next to useless.
Considering the OP's concerns and not knowing specifically where next his device is going, many assumed a niece Sally level scenario. And for many that IS sufficient.
Before the thread devolved into a destroy the phone in a creative manner sort of game, some serious and relevant discussion did take place. If you followed the link I presented in post #6 you would find a tool that fills the internal memory of the device with dummy info and erases it again. Combined with a few resets this would seriously hamper any data retrieval efforts. A serious solution was put forth.
But again, most don't need such extreme measures. They are simply handing their used device to a friend or family member, or perhaps selling it to another user rather than into the hands of the Russian Mafia.
I'm the first to advise people that they need AV where applicable, that data can be recovered by technically proficient individuals, etc... We all know here that the dangers are real and the thread was a sincere and realistic discussion until I devolved it with a joke which ran on.
Perhaps you'd share your recommendation on what should be done by anyone who wants to sell their used Windows Phone on the open market???