I've had similiar problems... My Sunon High Performance 120mmx35mm fan moves tremendous air @ 107 cfm..but it sounded like an overhead stove vent...I started a thread asking for advice...
I love the antec tricool 120mm fans. I've got on in my antec case and you cant hear it at the medium setting. Its got a low, medium and high switch built right into the fan. I picked mine up at Fry's for about $15. Happy cooling!!!