I have XTs (sorry I don't know what year) and I had problems with squealing fronts for a while (the rear were fine). I ended up trying a few different pads and finally found some that work well. They are very powerful. The squealing drove me insane for ages and I was almost ready to upgrade to a disc on the front. Maybe I should have gone with the Avids, after what I have read.

Oh, I have Avid levers.