yea, pravit prety much summed it up.

When i went to order my passport (the one to travel around the world =P)
The girl infront of me got turned down because she didn't have her birth certificate.

Difrent situations call for difrent peices of ID. Obviously, if u get pulled over by a cop, he wont ask for your school ID, but your drivers license. So, as pravit said, it just fits the situation...

And, if you really want to know what they look like, i can take pictures of my ID's =P

(I also have a picture of pravit's drivers license ! )