i use an airwhist air pump. it is so quiet its amzing. it is waaaay quieter than the rena 200 i used to have. even the tetra air pump that the guy with that annoying cat avatar has was'nt as quiet as this airwhist. and its a few light years quieter than that hagen 802 air pump i bought- that thing sounded like a bulldozer.
i recommend them heavily. best i have ever used.
figures its made in japan, not china or italy. nothing against italian chicks, they're usually smoking hot.