Ok, I'm gonna do it. 

I know that most of us love most of the episodes for varioues reasons. I know that I do. And I know we had a forum vote to mark the general rating of the episodes. 

But if someone held a gun to your head and asked to choose just one episode as our No. 1 favorite - which one would it be?

I've given this a good, long thinking myself. And I've come to the conclusion that if I have to choose one episode, my favorite would be ASiB.

Reasons is as follows:

It can never be from S1 because of John's constant annoyance and underdog-feeling (see different thread for more details)
It can never be from S3 because Sherlock and John aren't living together in 221B.
So S2. It can't be HoB because they aren't in 221 B and running across London. (Otherwise I LOVE this episode).
It can't be TRF because it's too sad.
So ASiB it is. It has it all: The two boys in 221B, the two boys having fun and enjoying each other, a good story, Sherlock growing... it has everything, but it doesn't have the final sadness you find in the cliffhanger episodes.

So - which one episode is your favorite, and why?