While I'm not entirely sure that 16 year olds can vote responsibly, I'd rather have them making some irresponsible votes initially and then actually voting throughout their lives rather than never learning to vote (which seems to be the case these days). I think the ideal voting age would be such that every individual would be able to vote once during high school (regardless of what year they are in). This would enable tie-ins to civics classes, etc. Of course the education curriculum has to be there for this to make sense.