Phew - caught up with all the posts!
I absolutely loved last night's Sherlock. The episode zipped by and I watched a lot of it with my hands over my mouth in an "oh my goodness" way!
Martin Freeman was superb. The bit at the beginning with the therapist was quite moving, but the graveside scene was very very moving. The part when he touched the top of the gravestone made me well up. The bit where he was asking Sherlock not to be dead and his voice caught on the word "dead" was done so so well. Heart wrenching.
When did they visit the grave by the way? Was it a short time after the funeral or was it at the 18 months after stage when Watson was seeing the therapist?
I have changed my mind about Moriarty. Thought he was perfect in last night's episode. The bit in the journalist's flat where he was pretending to be all frightened and Sherlock walked towards him, you just saw a little evil glint. Fantastic acting. No idea if he's alive or dead.
I've watched the end bit again because DH reckons he threw a different body off. I don't think so because you see him standing on the ledge and then taking a step forward. But we didn't see him land. I agree with what other posters have said that he very deliberately told Watson where to stand. I'll have to watch it again - oh no, what a shame
- but yes, he must have landed in the lorry and then a fake Sherlock was brought out with the cyclist deliberately knocking Watson over to delay him.
Mycroft is definitely in on it and will help to clear Sherlock's name when he comes back.
Finally - apologies for massive post! - at the grave scene when Watson was talking I kept saying to DH "he's not dead, he's not, he's not". Then when the camera panned across at the end to show him, I will confess I was doing a happy dance with "he's not dead, he's not dead". 
Sorry for mammoth post!