A personal preference would be 24-35-50-85 and 135. But if I were limited to 3 lenses they would have to be 24 - 50 - 100mm

Canon did make a special glass back in the 70's which used something 'extra' in the elements of their better lenses, but I seem to remember that this glass was prone to deteriorate if it was allowed to be exposed ton the elements but when they were new their resolving power was better than anything else that other manufacturers could get close to. Does anyone else remember this. I seem to remember it was used in their 85mm F1.8 FD (with breech lock) lens