My 2 oldest are gifted but in very different ways.  It was hard for me to even see that my 2nd child was, because he seemed so normal compared to my first.
 
I liked what Suki said here…

“I am a high school dropout and Stanford graduate. I was just so bored at school! My son is more like my husband – he keeps himself occupied by learning deeply about the things that other kids just skim the surface of.”
 

My first son is the one who delves deeply and THINKS about everything on a level that most adults don’t go to.  He also has some learning challenges, so he doesn’t “appear” gifted in some ways.  But if you sit and talk with him, it becomes apparent that he definitely delves deep.
 
My 2nd son was SOOOO bored in school and just learns things quickly, but didn’t seem to want to learn anything deeply.  Once I pulled him out of school, he suddenly was able to find what he loved to learn about and apparantly it is history and piano (at least right now.) 
 
It is just interesting how each child has their own way of showing their gifts.  I had my 2nd one tested for GATE and my older son says he will be so mad if he gets in GATE, because “He can’t be smarter than me.”  That is tricky to respond to.
 
So I explained it in this way.  You think more deeply than he does so in many ways you will always be smarter than him because you go deeper.   But he is smart in his own way to, a more typical type of smart.”