Maybe not every, but sth like 95%?
The far majority of Germans in the regular army were just people who thought they were fighting for their country, for their family and friends. They weren't nazis and barely had anything to do with the regime. They were no different from the Allied soldiers they were fighting.
I'm sure VonMudra can give you an estimated percentage of how many Germans (soldiers) were true nazis, but it's not going to be much.
Honestly, it's hard to say. Whilst party membership in the Heer was discouraged, it was encouraged in the Luftwaffe, with many of the pilots being sons of party officials and such, eager to put their sons into what was considered the most national socialist wing of the military. As for the Heer, there may have been relatively few party members, the vast majority of German soldiers supported the regime, and knew at a minimum of what the propaganda machine had told them about the fate of the Slavs (slaves on farms for German colonists). Soldiers were indeed actively told that they would be awarded with land and slaves in conquered lands in Russia, and anti-Semitism ran high, being as it had been bred into them for over years by the party propaganda (and generations of anti-Semitism before then, something which is still rampant in Europe it seems...). Probably the only major nation that had a higher war crime rate in their army would be Japan. The Heer generally acquitted themselves well against the Western Allies, but often untermensch were punished for performing well against Heer troops. During the Polish campaign, many thousands of Polish wounded and POWs were executed en masse for no other reason than infuriating Heer troops for their resistance. Many others were either denied medical treatment and left to die, and it was also common to simply shoot surrendering Poles out of hand, as a punishment for their hard resistance. This began as soon as the first shots were being fired, for instance, the 4th Panzer Division used civilian human shields at Mokra, and tortured and executed captured Polish air men from a plane which was shot down. The 4th Panzer continued to use human shields in Warsaw and other battles, and their parting gift to Poland on the 18th/19th of September, before being withdrawn, was to mass execute hundreds of Polish POWs, as well as a few towns, by forced drowning.
On the western front in 1940, the Heer, for the vast majority, preformed and conducted itself well. In this case, it was more due to fighting troops they did consider as 'equals', unlike the Poles. In the cases where it faced colonial troops, it acquited itself with a similar savagery, and at least 2,000 or so colonial troops were executed in mass shootings by Heer troops in France in 1940. On the Eastern Front, execution of POWs was common, and the Heer did preform with much savagery to the populace, which was reciprocated in kind by the Soviets upon entering Germany in 1944 and 45. Gibergsjager units also had a notoriously high crime rate, the most heinous of which were the burning of the Lapland in 1944, and the mass execution of the Italian Acqui Division in 1943.
Really, the only part of the Wehrmacht that did not have a high rate of nazi membership and/or governmental support were the Kriegsmarine. This was due to a number of reasons. Navys in any military are often highly conservative, and conservative in German in the 30s and 40s was in line with monarchism, and against totalitarianism. It was also, in essence, a backwater, a place to send those who were felt embarrassing to the party and to the government, and those who were seen as dangerous to morale. Thus, many anti-government officers and men found themselves shuttled away to live and die in the depths on u-boots. This did have another effect, with the Navy being the most successful at sheltering Jews in it's ranks, with many reaching officer status. By comparison, the Heer contained several thousand Jews and Mischlinge, but those in the ranks often only did so by fraud on their behalf, and include many accounts of being nearly found out and killed by their comrades in arms (and, for those who looked stereotypically Jewish, a whole host of anti-Semitic jokes at their expense).
The myth of the Good wehrmacht is one that was propagated by the allies after the war. This is entering into a whole new minefield. The myth was namely one meant to rally support behind re-arming Germany. By pretending that the Wehrmacht were good, knew nothing of the crimes, and behaved totally honourably, NATO was able to allow the formation of the Bundeswehr under the tutelage and direct officership of Wehrmacht veterans. For more info, I'd say a good read through this wiki is in order:
http://en.wikipedia.org/wiki/War_crimes_of_the_WehrmachtIn general, you see an upsurge in Heer crimes when facing "untermensch" troops, especially when those troops offer stiff resistance. You also see tons of mistreatment of civilian populaces, and mass anti-Semitism that did boil into outright genocide many times.
Just realized I need a photo. Well, here's one:
Photo taken by a Heer soldier after the execution of a row of Polish POWs. This photo is often said to be from the massacre in Ciepielów, however, without anything linking it to that, it is more probably simply one of many small time executions of Polish POWs that went un-documented by any but those who were there to witness it. One reason for why Polish KIA was as large as it was in the campaign was simply this- the slaughter of Polish POWs.
