It’s hard to pick a “Greatest General” given the disparity of technologies and eras.
I’d rather pick a list of 5.
Genghis Khan
Hannibal
Khaled bin Al-Waleed
Von Manstein
Ariel Sharon
Mighty good choices! In particular, Von Manstein is a great choice which also points to the fact that WWII had the, uh, I guess, benefit of having some mighty great generals all over; on the German side, I’d pick Guderian, Rommel, and Von Manstein. VM’s memoirs are on my eventually-I-will-finish-it list of books I’m reading. The sharp focus of his mind comes through in his text.
I’d add Sepp Dietrich to the German list, not for strategic thinking (he had none) but for sheer ass-kicking fighting-man abilities — but the guy kinda creeps me out. He was no doubt about it a straight talker, which may be why he was the only man Hitler trusted. Nominally he reported to Himmler, but Dietrich reported in fact directly to Hitler.
Patton was the greatest of the US generals in WWII, although the snarky Omar Bradley neither gave him credit for knowing what he was doing the whole time nor for his accomplishments (meanwhile, Bradley showed flashes of minimum competence). It’s probably cheating (and will probably tinkle off some people here), but the greatest of the Pacific Fleet command belongs on the list of nominees, IMHO. The toughest fighting of the war for US forces at least was in the Pacific, and in Italy (due to the terrain, rather than the Italians).