When I first picked up minecraft I hurried to build a small dwelling within the side of the mountain, and eventually carved it out with tunnels and passages going everywhere. You couldn't see much from the surface.
My more recent (
main) world saw me start by going to the top of the highest mountain I could see and then building a small house on top. I eventually replaced the dirt walls with secure-feeling cobblestone followed by completely changing it to glass (so I could see what was lingering outside of my house). I then built a mine down to bedrock and hollowed out a fair section at the bottom... But I only go down there when I need more cobble.
After that I then built an epicly long skybridge back towards my spawn point with a tower there to access it. I then just branched out everywhere into many different directions essentially creating my own sort of "freeway" in the sky.
So in other words, "I have no idea what is says about me

"
TL;DR
A very outdated video of my base:
http://www.youtube.com/watch?v=J4GEnEt46Hc
(It has changed a lot since then).