Found a natural Stronghold, Happy Dance Time!
Sadly there is an abandoned mine going right through it, notch needs to fix that. New terrain is cool, but often intersects and ruins itself.
Iron Doors with buttons, and what look like little jail cell, if notch expands upon these, I can see some real potential to reach an Oblivion level of dungeon exploring fun.
Something else of note, Strongholds use the regular cobblestone stairs even though there are Stone Slab Stairs, or something like that. odd.
And another thing, the Auto Lighting in the Strongholds hasn't worked yet for me. Not sure if I'm only one with this problem.