Optically Canon 50mm f1.4 and 100mm f2.8 macro tie, both very sharp with good contrast.

Then it’s a toss up between the canon 17-40 f4 L and the 24-105 f4 L both optically on a par with each other,(not quite as sharp as the primes) different uses. Very sharp on a 1.6 crop DSLR with good contrast.

In that range the Canon 28-105mm f3.5-4.5 USM II , optically close on the heels of the 17-40 f4 L and the 24-105 f4 L, not quite, but about £400 less.

On a par optically with the 17-40 f4 L and the 24-105 f4 L is the Canon  100-400mm f4.5-5.6 L IS, of course it has limited uses.

They wouldn’t have made the cane if you weren’t meant to break the rules