I would say Germany was the most interesting. For the first few years, it was the one doing all of the conquering. It had a land empire from north Africa to Scandinavia. It developed the panzers, the V1 and V2 missiles, and a lot more besides. There was a fascinating system of propaganda and terror used to keep the population in line, enormously different to anything we could possibly imagine today. Russia is fascinating for the same reason, as well as the fact that it had to first hold off an enormous German assault and then fight back to capture all of Eastern Europe.
Meanwhile, in Britain, Churchill gave some speeches and a few children got onto trains. It wasn't nearly as interesting.
(Former) Lead Moderator and (Eternal) VGC Detective 
