It is my opinion that if Germany had won the First World War, the world would be a happier place today with 60 million more people.
The German economy managed to recover after the war, and that was with the crushing terms of the Treaty of Versailles, thanks to American loans to the Weimar Republic. The peace terms with the Allies and the Central Powers would have been favourable to the Germans, and would have allowed their economy to recover rapidly. The Imperial Monarchy, strengthened by its victory, would have continued for at least several decades. Rebellios rif-raf such as the Nazis and Communists in German would not have been tolerated.
Germany would also have conserved the territories it had been granted under the Treaty of Brest-Litvosk, which would further have helped the German economy. The Kaiserliche government would not have regarded the turmoil in Russia with a favourable eye, and would probably have given much support to the White Russians and would maybe have committed its armed forces to the region. The fledgling Bolshevik republic would have fallen, and communism in Russia would have been nipped in the bud.
The Ottoman Empire was pretty much doomed anyway, and would have crumbled soon or later. Austria-Hungary would have taken its place of the sick man of Europe, however it could have survived as a constitutional monarchy with a sort of federal government with the Kaiser being the binding figure between the different nationalities.
Britain would probably not have been affected by communism or fascism, as the British are not all that keen on such religious politics.
France, on the other hand, was affected by a fairly strong communist movement in reality, so it would not be implausable to say that the commies would have garnered much support after the country's defeat in the war. As the rise of communism invariably leads to the rise of fascism, there would have been the same conflict between the two groups as that which had marked Italy and Germany. Like the latter, France could have gone fascist. Italy would probably have gone fascist in defeat as it did in victory. However, the duo of France and Italy would have been the military equivalent of Laurel and Hardy, so I doubt the world would have had much to fear from these two nations.
Germany would have superseded the Royal Navy under the terms of any treaty and colonies would also have been given over, such as perhaps Nigeria, Zanzibar, Kenya and chunks of French West Africas, as well as Asian possesions such as British New Guinea.

So, no communism, no naziism, and no holocaust.