Here's one topic I've never seen discussed -- does Voldemort only prey on witches/wizards in England? Why don't we hear about anyone from Beauxbatons or Durmstrang who are attacked, killed, etc.?
I remember Draco talking about how he alsmost went to Durmstrang. Hermione said they were more into the dark arts and with Karkaroff the former death eater, that may be a training camp, big conspiracy theory! Phlegm never really comments on Voldemort, so who know about the other schools for sure.