While I'm mostly talking about people, I could also use some info on the value of non-human things lost. This is for an argument with a friend that claims that the Western Allies could of won WW2 on their own.
Your friend is wrong. Very, very, wrong.
John Ellis gives the following figures for German losses of tanks, armored cars, tank destroyers and self-propelled guns:
Western front: Approx. 4,000
North Africa: Approx. 2,000
Eastern front: Approx. 44,000
Further, you generally had between 60-80 percent of all Axis forces concentrated on the Eastern Front at any given period after 1941. The Soviet Union absorbed the majority of German military might. There are precise numbers somewhere, I'll have to look them up though.
This isn't to say the Soviets would have won on their own. It's possible, but there's way too many 'what ifs' to make any kind of accurate guess...and we wouldn't want to get into speculation within the hallowed halls of /r/askhistorians.