I found this interesting site that lets you listen to all of the fans they sell. Every fan on the list is probably an example of what not to buy. If you want to hear fans that make you want to pull your hair out, go to the following link
http://www.sidewindercomputers.com/tecar.html
Fans NOT to buy
Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee
lol listen to the fan power!, http://www.frostytech.com has a samples of the heatsinks they test now as well and they're more up to date, in my experience and from a lil titbit from the forums I picked up is that anything with a Amp rating of 0.10 is too loud, And I think this theory is very right (credit's to MikeC I think for this one)