3Gs ftw... Everyone loves it grooved and dimpled!
Is that with new pads? Have you removed any lip around the outer edge of the old discs to stop it rubbing off the edges (gently tap the edge with a hammer all the way round - time consuming but...)? Copperslip all around the outside of the new pads to stop them catching? There's something to do with toothpaste too but I've never had to do it so I can't remember the details...
Loads of things to try before the expense of changing the discs.
A