The first few times I travelled out of the country were around 2003 and 2004. At that time, I didn't recall being asked to declare DVDs in the customs declaration form.
A few days ago, I came back from Sydney and was surprised to learn that DVDs (and VCDs) should be declared, along with the usual electronic items. At that time, I had with me 2 DVDs which I purchased from JB Hifi (pang souvenir lang, as the prices here are cheaper - at least basta sale). Per the Bureau of Customs passenger guidelines, DVDs are considered regulated items that require import permit/clearances.