We'll assume you're asking about the American Army which included the Army Air Corps (later the Air Force) during WW2. One commonly hears that 229,000 Americans died during World War Two. That is the ARMY figure, however. Overall American deaths (413,000, of which approx. 300,000 were combat deaths) were spread pretty much equally between the two theaters. We can assume, however, that Navy and Marine casualties were much higher in the Pacific while Merchant Marine and Army casualties were higher in Europe. Going with this information, I would surmise that the U.S. Army (again, including the Army Air Corps) probably lost about 120,000+ men in Europe during World War Two.
My wife and I visited the D-Day museum in Caan, France in September, 2008. (The museum is spectacular.) In it, there is a plaque with the list of deaths by country. They are as follows:
Allied Powers Russia 1,800,000
France 1,375,800
United Kingdom 908,371
Italy 578,000
Serbia 278,000
Romania 250,000
United States 114,000 Belgium 38,716
Central Powers Germany 2,033,700
Austria/Hungary 1,100,000
Turkey 804,000
Bulgaria 87,500