+1 on what cyco-dude said.
If you've got a convenient exhaust let the front fan pull air *in* the case, through the rad.
If you have no exhaust, let it pull air *out* of the case, and make sure there's some kind of hole to make up for an intake.
If you want *more* silence there are ways to go (fanless or watercoooled PSU, HD blocks + silencers, GPU block , NB block and so on). If you really want to go this way tell us, i have plenty of bookmarks about this
