I think Mikoyan is going to shoot me but I voted "Other" for Hungary.
The Hungarians did us a favor when they refused to allow their erstwhile ally, Hitler, to use their trainlines for the invasion of Poland in 1939. However, for some reason - effective propaganda? - while nearly everyone surrounding Hungary had great respect for the Hungarian Army, its actual performance was pathetic. The Soviets in the months after the German invasion in 1941 bent over backwards and begged Budapest not to join Operation Barbarossa, offering them the banners they'd seized in the failed 1848-49 Hungarian Revolution as well as recognition for the real estate deals Budapest had made with Hitler that gave them back some of their pre-WW I lands. Eventually though an airraid on an eastern Hungarian city, Kassa (modern Kosice, Slovakia) brought Hungary into the war against the Soviets. (This airraid, while never proven, was almost certainly a German--staged stunt to get Hungary in the war.) The Hungarians joined several other Hitler allies fighting in Russia, and like most of them the Nazis trusted them little and put them in "safe" areas. The problem was that after the Battle of Stalingrad, those "safe" areas began to disappear, and just about everywhere became a front line. The Hungarians had an unfortunate meeting with the Soviet Army as it surged towards the Don River in January, 1943 at Voronjesh - and the result was 150,000 lost out of a total 200,000 on the Hungarian side. (Hint: It wasn't a Hungarian victory.)
Hitler had known for a while that the Hungarians were secretly negotiating a switch to the Allied side (based on a bizarre Churchill scheme to invade the Balkans just like they did in the First World War, giving the Hungarians the belief that they could switch the moment the Allies reached the Hungarian border). However as the Soviets approached Hungarian territory in March 1944 Hitler had the Wehrmacht occupy Hungary, and as the Soviets invaded Hungary in September 1944 it started getting serious. After a German betrayal of a truce at the first major battle in Hungary (Debrecen) the Nazis tossed the Hungarian government out and installed a bizarre small band of Hungarian fascists led by a guy who made Hitler seem normal, Ferenc (Franz) Szalasi. This madman loyally fought the Soviets at every advance, guaranteeing that much of Hungary - so far untouched by the war - would be laid waste. As the Soviets advanced the Americans bombed Budapest from Italy. Huge battles were fought and lost all across Hungary, including in Budapest itself and even the final westernmost city in Hungary, Sopron. The place lay in ruins and Hungary was branded by the Allies as Hitler's most faithful ally, all because of the idiocy of one man. (Some captured Hungarian soldiers did try to form a liberating Hungarian unit in the Soviet Army to fight for the Allies but the Soviets said "Nyet".)
So the Hungarian contribution of the war militarily was essentially nil, and was to no one's - not even Hungary's - benefit. To be fair, Hungary was a major provider of foodstuffs to the Wehrmacht and provided much logistical support through engineers and transport. A Hungarian professor of mine, however, once put it this way: "Hungary allied itself in 1914 with the Germans, and they lost. Hungary allied itself in 1939 with the Germans and they lost again. Hungary then allied itself with the Soviets in the Cold War, and they lost. Now Hungary is a NATO ally; clearly NATO does not read history books...."