If you're using road-style holders, the Dura-Ace 7900 inserts are excellent. Kool-Stop's salmon variants are also good. For brakes that simply will not stop squealing, the Yokozuna salmon pads work wonders.
Thanks for the tips. I'm waiting on some Shimano CX50 canti's to arrive. I do have some traditional road style brakes so will swap out the cartidge holder so I can get some some of these better options down the track.
