I don't think that CR is the most atheistic country. In Europe it's the third (I think that Estonia is first and Sweden is second). And I don't know how it is in compare to rest of the world.

And even this czech atheism isn't any clear thing. In CR many people say that they don't believe in god, but they believe in "something". The something can be fate, destiny, live force, etc. One Czech theologian call it "něcismus" (somethingism). So I'm not sure if it can be called true atheism.

But basically you can meet in CR people of all kind. Personally I know some protestants, few catholics, many people who just don't care, some atheists and one or two hard core atheists, who I find annoying in the same way how any other fundamentalists (they have their truth and this is only truth and they have to spread it everywhere).