Internal geometry format

Hi, I'm just wondering how everyone stores geometry data internally once read from disk or generated, considering clean interface vs fast access, easy modification and display method (display lists, vertex arrays) et cetera.

[RandyU]

I don't know about everyone, but I create my special format. It encodes all commands like
glBegin, glEnd, glVertex3f(x,y,z), glNormal3f(x,y,z), so it's easy to read it into display list. I even have a little editor.