Brake pads are supposed to touch the rotor. The only thing that moves pads away a little bit is the square O-Ring rocking forward as hydraulic pressure pushes on the caliper piston, and rocking back pulls the piston back in when pressure is released. The purpose of shims is to reduce noise. Nissan put shims on OEM. A bad bearing on the half-shaft is a possibility but I suspect the noise is coming from the pads on both sides like you are hearing. I can't agree more with MyOwnMechanic report on his experience.
http://www.automotiveforums.com/vbul...d.php?t=450222
I put Akebono pads on my used Altima rotors and I would describe the noticable improvement as feeling sticky. Yesterday afternoon I put new front rotors and new Akebono pads front and rear on my daughters '01 Accord. She is amazed with the improvement and feels the same sticky stopping sensation. Premium pads cost more because they result from the latest technology.... and new shims are included. Competitive priced pads are older technology and you purchase shims seperatly. If you determine that the noise is from the front brakes, return the pads and try another brand.