I've been waiting for this for about a year, and hoped so much it would be good... and it was brilliant. Absolutely brilliant!
The first thing that made me say "yeah" out loud happend before Sherlock was even on screen: Watson and Stamford meet in the park directly around the corner of Montague Street, where young Holmes lived! On my first Holmes-pilgrimage to London about a year ago, I especially booked a hostel on Montague Street, and I often sat on the same bench Watson and Stamford were sitting, smoking a cigarette (Holmes is right about London being a difficult city for smoking, haha) and just enjoying the fact that I was in London, right were Holmes lived before he moved to Baker Street. This might sound a bit obsessive, but it made me very happy :). And there were many more things like that, just small details for the fans, from the fans - you could see and feel it every second of the movie: the writers are just as much in love with Holmes&Watson as I am!
Second great thing: Sherlock's leap of joy and general exhilaration about crime and serial killers ("Love those, there's always something to look forward to!") was absolutely spot on, for me this is so exactly Sherlock-from-the-books, nobody ever got this close before. Cumberbatch is a terrific actor - nothing ever looked forced, he managed to play aloof, serious, giddy, authorative, intelligent, childish, and a thousand more conflicting personality traits - and tying them together into one fascinating characterization. Really outstanding.
All the deduction sequences, especially the investigation of the woman in pink, were intense, fascinating and believable. And Watson's praise :). So cute! And the map scene - Sherlock and London, his one true love (of course there's Watson too, although for me they're "just friends", if you can say "just" to such frienship and love :).). Yes, London looked great, and you really got the feeling of Sherlock's bond with the city, all its hidden ways and passages, and it works in modern London just as well, because London still feels so old and mysterious.
Loved Sherlock's clothes too - his whole appearance - the fitted suits brought out his tall, thin stature, together with his elegant, even old-fashioned posture and way of moving - reminded me of Jeremy Brett in some scenes.
One thing I didn't quite get - was it implied that Holmes did take illegal drugs before, and managed to substitute them with the nicotine patches? If that's the case, I think that's a perfect and plausible "updating" of the drug thing. I don't like filmmakers to leave the whole thing out altogether, but on the other hand I think it should not be exaggerated; for me, it is on a level with the not-eating, wall-shooting and general weirdness of Holmes.
Other parts I particularly loved: the mess and Mrs. Hudson, the restaurant scene (everybody seems to love that scene!), the drug raid (Watson's "Come look everywhere, no drugs here!" ect. was so funny), everything with Lestrade in it, the way Sherlock says "The gun" (I don't know what it is, it's just great), the blanket, oh I think I liked everything :)!
Can't wait for next Sunday.