(I should also note that the words "Satan," "Satanic," and "devil" are never mentioned in the movie, as far as I remember. [Spoilers?] The secret society in the movie seems to resemble the Hermetic Order of the Golden Dawn a lot, and there's some arcane (and historically inspired) ooga-booga to it, but the implication is that it's not evil per se; it's Lord Blackwood who wants to pervert its purpose. I wasn't terribly clear about that, and after I thought about it, I realized that I might not have even described Blackwood's activities accurately, either--but the movie opening with an attempted human sacrifice made me go, "Oh, Hollywood Satanism, sure." So that's where that came from.)
I also spent a good bit of yesterday afternoon rereading the first two Holmes novels, A Study in Scarlet and The Sign of the Four. The former is interesting because it shows you how Holmes and Watson meet, but while the character of Sherlock Holmes is pretty fully realized from the first page, he's initially written as being a bit naive about anything not helpful to detecting, such as, you know, the fact that the sun is the center of the solar system (I am not making this up). I think Doyle eventually realized that this didn't make sense, because everything is potentially helpful to detecting, and so by the second novel (the stories didn't appear until afterward), Holmes is far better read and knowledgeable about life in general. If you really want a classic, full-blown Holmes adventure, I would recommend that second novel. It doesn't stop dead in the middle for a huge third-person account of someone else's lovelorn Mormon revenge drama, of all things (special guest appearance by Evil Brigham Young!); you see a lot of classic Holmesian elements (the disguise, the hapless police inspectors, the Baker Street Irregulars, the cocaine); and it shows you how Watson actually met Mary Morstan. There are, however... well, there are some facepalm-inducing racial issues with one of the villains (and that's not even getting into the treatment of the aforementioned Mormons), which is why I suggest reading an annotated version (I have the Klinger, haven't read the Baring-Gould) to offset the Wow, Victorians Were Offensive! And How! aspect of it.
Of course, The Hound of the Baskervilles is also a classic, but Holmes is offscreen (offpage?) for a bit of it. The Sign of the Four is more of an adventure (also, the movie seems to have borrowed a number of little things from this one), whereas The Hound is more of a slow-burning atmospheric suspense kind of thing. Also: less racist. Yay!
I feel the question coming on, so: if you just want some short stories to read, I would definitely recommend "A Scandal in Bohemia" (the Irene Adler story), "The Adventure of the Speckled Band" ("Terror! SHEER TERROR!"), "The Adventure of the Copper Beeches" (the Granada episode starred a young Natasha Richardson, IIRC), "The Naval Treaty," and "The Adventure of the Second Stain," although the more I look through the list of stories, the more I want to recommend, so I'll stop there. (Really, pretty much anything in that first collection is good.) I would highly avoid the last collection of stories, for reasons explained here ("JELLYFISH!!!"). Although, that is the entry I pulled the Epic Love excerpt from, so maybe you will want to read "The Three Garridebs," I don't know.
Back to the movie, I think I have figured out what the Significant Crow was about. See, that was the part that upset me, because the Significant Crow that followed Blackwood and his misdeeds around seemed to indicate that all the supernatural stuff was for real; that's why I was all like NOOOOOO THIS IS NOT HOW YOU DO IT WHYYYYYYY. But then, at the end [MASSIVE SPOILER], Blackwood gets ironically, "accidentally" hanged, Significant Crow is significant, etc. So what I think was actually going on was that Blackwood really was messing with things he either didn't understand or couldn't handle--if only by taking them in vain, as it were, and pretending to use them; maybe it was related to the "actual" secret society and its arcane powers--and the Significant Crow was following him around observing all this, as an emissary of Things He Should Not Have Messed With, and thus, at the end, was present for his judgment, and might have actually caused it. I mean, not that the crow literally messed with bridgey-whatever stuff, but that it was the embodiment of the powers that had been biding their time and were finally like, "Yeah, you're done now."
Heh, true, there was a bit of an implication there. By the way, I think the bird was a raven (which are close relatives of crows), because it was Tower Bridge, which is famous for its ravens.
The earliest known reference to a tower raven is a picture in the newspaper The Pictorial World in 1885. This and scattered subsequent references to the tower ravens, both literary and visual, which appear in the late nineteenth to early twentieth century place them near the monument commemorating those beheaded at the tower, popularly known as the “scaffold.” This strongly suggests that the ravens, which are notorious for gathering at gallows, were originally used to dramatize tales of imprisonment and execution at the tower told by the Yeomen Warders to tourists.
THE CROW KNOWS THAT, OKAY? THE CROW KNOWS.