The canonical genius has to be Albert Einstein, who was known for humility. As to some others, people make history as geniuses for (1) doing genius things and (2) making sure everyone knows they're the genius that did it, so you have to consider the effect of (2) when you try making a list.
If they manage to do #2, they are still a genius, which contradicts the notion that geniuses must be humble.
Personally, I prefer a bit of arrogance so that people clearly state what they believe and why, even if it is a bit blunt. The clarity of this approach seems to lead to better ideas, since my personal observation is that great ideas also tend to be fairly simple and can be stated in a straightforward manner.
Plus, when an idea is clearly stated, it is easier to know if the idea is right or wrong, which is necessary for the humility bit of self questioning.
