Most of today's 80+ PSU's are pretty much inaudible at normal load levels and 99% of the time the quietest component in the system (which renders it inaudible), you're still going to be using some case fans and CPU fan or am I wrong? There are drawbacks to a fanless design as well, I suggest you check this article out: http://www.tomshardware.com/reviews/power-supply-silent-passive,3189-11.html
As long as you keep the system well ventilated and your ambient temperatures aren't too high there shouldn't be any problems, but then again in order to keep it well ventilated you're going to need some fans and chances are they'll be louder than that of a good quiet PSU with fan pretty much defeating the point of a fanless one.
There aren't many manufacturers who make good fanless PSU's but anything from seasonic/antec/silverstone/corsair that is 80+ I'd deem as trustable, this specific one has excellent reviews: http://www.newegg.com/Product/Product.aspx?Item=N82E16817151097
, but they don't ship to belgium there, don't know of any pc part online store from belgium either.
Look for at least a 350w PSU that is 80+ that's either by seasonic,antec,XFX,silverstone,PCpower&cooling,corsair, maybe I'm leaving a few out but those are the ones that have proven to make solid products over the years IME, any of those should be fine.