The Most Impressive Philosopher Ever?

I've been impressed by jerry foder, thomas nagel, peter strawson. I wouldn't like to rank them one against the other. Michael dummett is an absolute pain to read on the age if you've never ever heard him speak. The most impressive was parfit. Both parfit and williams were supervisors of my dissertation work at oxford and at cambridge. Williams was whittier and more zzling than parfit.