I remember in Oblivion I absolutely loved secret rooms and pathways, like clicking on a candle on the wall, the candle makes a noise and a secret door opens revealing a room with treasures etc.

Anyone else loved this? are there any info about that coming in skyrim too?

I've heard no info on the subject, though there probably will be some secrets.

I read one preview where a note revealed the location of a secret passageway to a bandit lair under a house. I'll see if I can find the link, but there's so many previews out there that I doubt I'll find it...

Found it! I underestimated my Googling skillz:

http://www.gamesradar.com/skyrim-preview-secret-of-pinewatch-sanctuary/

Wow that looks awesome, thanks

cool I alwayse loved that in morrowind and even more in oblivion going behind every tapestry and eventually finding a treasure room or a torture chamber or a trap door to a counts bedchamber.

YES!!!! Secret passages are amongst my favouritest things ever!!!! If I win the lottery the first thing I want to buy is several elaborate secret passages. So happy to hear they are back in Skyrim! This has actually made my day!

I remember reading a preview where it was written that certain caves were so big that allowed you to pass through a mountain and exit on the other side.

Yes, we are going to see a return of "Secret Loot Locations" like in Morrowind where you needed to do a whole Park-our to reach some loot.