These are the number of deaths that occurred (civilian and military) as a result of WWII in some of the combatant countries:
Great Britain 350,000
USSR 20,000,000 (this figure is almost twice as large as those above put together)
My source is the Worth Press Timechart History of World War II by David Gibbons. The Soviet figure is on the conservative end, compared to other sources I have seen. If I'm not mistaken, deaths in Poland were something like 6 million, and those in China much higher than that.