Because this PC is for HTPC use, I would like to get rid of all noise factors. That's why I would need to replace my Antec Basic 350w with some fanless PSU which is 100% compatible with the Cooler master elite 360 case and the Gigabyt rig, and which can still do the job for HTPC and light gaming, and doesn't cost too much.
I live in Belgium, but I could order the thing from any webstore that delivers to Belgium.
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... ,
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=N82E168... , 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.
Be Quiet Efficient Power F1 350W (€60 @ Alternate) http://www.alternate.be/html/product/Voedingen/be_quiet!/Efficient_F1/618007/?tn=HARDWARE&l1=Voedingen&l2=tot+400+Watt
Has a noise rating of 14-27dBA and Be Quiet PSUs are generally known for their low noise.
It is basically a rebadged FSP Aurum Gold 400W, except obviously with lower wattage and a quieter fan.
You'll have to pay at least ~€100 to get a fanless or semi-fanless model.
I don't agree that any PSU that is 80 Plus certified is automatically going to be quiet, this is because I know of a few PSUs that even have the 80 Plus Gold and Platinum certification which are not quiet.
I've had an FSP Group 400 watt fanless running for about 3 years now. It was the only option at the time, but I would have preferred a better unit. Temps in the system jumped up quite a bit when I switched to the fanless, so I had to increase the size of the CPU and GPU heat sinks.