Feb 16 2013: There is a study by Brickman et al. (http://psycnet.apa.org/journals/psp/36/8/917/) which shows that people who have recently had an injury which led to paraplegia weren't unhappier than people who had won in a lottery before (or to be more accurate: those who had the accident didn't expect to be unhappier in the future).
So I think that this shows quite well that there are factors which are much more relevant to be happy, e.g. friends and family.
To answer your question: no, money can't buy happiness.
Aug 27 2012: Even if that's true, you should e-mail the TED team to change it in the original transcript and not just change it by yourself in the (German) subtitles.
TEDCred score: +7.10 TEDCred reflects your contribution to the TED community.
A comment on Conversation: Can Money Buy Happiness?
So I think that this shows quite well that there are factors which are much more relevant to be happy, e.g. friends and family.
To answer your question: no, money can't buy happiness.
A reply on Talk: Damon Horowitz: Philosophy in prison