@Ionus,
German nobility, "as a group of people", certainly didn't resist Hitler the most. If you're arguing that out of the assassination attempts that arose from within the military, a disproportionately large number of officers were noble, then the reason might be that a disproportionately large number of all officers were noblemen. That said, resistance in noble circles was practically non-existent until 1939, when Hitler's aggressive foreign policy changed to open declarations of war. Members of German nobility had a lot to gain from the NSDAP's rise to power. After World War I, the treaty of Versailles imposed dramatic reductions in military numbers on Germany. Many members of noble families had traditionally been career officers, and unlike conscripted soldiers, they found themselves without any peacetime skills or jobs after they had been stripped of their military ranks. They welcomed Hitler's policy of rearmament and of dramatically increasing military numbers after 1933. Only .15% of the population were nobility, but in Germany's new army, 15% of all officers were noblemen.
The fact that the NSDAP defined citizenship and racial purity in terms of bloodlines also didn't hurt their reputation in noble circles, and even Hitler's declared goal of colonizing "the East" was received quite well in some noble families.
The military aspect and the involvement of noblemen in assassination attempts like
"Operation Walküre" have been portrayed way out of proportion after the end of World War II. The conspirators of the 20 July plot included people from all kinds of groups - former members of the Social Democrat Party, the Center Party, the DNVP, the church etc.
Out of the 200 people that were executed and the 5000 that were arrested as a consequence of the attempted coup, the Gestapo rounded up anyone who was even remotely connected to the plot, and in many cases used the opportunity to settle scores that had nothing at all to do with the plot. There was no "purge" of noble officers after the 20 July plot, because those officers stood firmly behind Hitler and the NSDAP.