I'm in the rarity: I didn't much like it. Jude Law was a great Watson, and Downey was quite good as Sherlock Holmes (in particular, he nailed the way Holmes goes into a dreamy state making his deductions, which pleased me no end because no other adaptation has really done much with that, which is one of my favorite Holmes tics), but the case wasn't worthy of the characters and I wasn't wild about Rachel McAdams as Irene Adler. The sets were too huge, too sprawling, too lush; they didn't work to draw me into the story (as did AVATAR's CGstravaganza), but pushed me out of it (as did PIRATES OF THE CARIBBEAN III's final swordfight, during a ship battle, inside a giant whirlpool) -- the story wasn't gripping enough, so it felt like the money was being spent in an effort to make up for it.
It was just... meh. I get the feeling that I'd have liked it if I were a slasher, because pretty much every scene had Holmes and Watson exchanging innuendoes, but while in recent years I am increasingly inclined to wonder if Doyle were hinting at Holmes being secretly gay and drawn to an oblivious Watson, I don't share the "It's Better If They're Fucking" worldview. I think the characters are awesome! I am there to watch them being awesome! This was... just okay.
I did really like the little filmmaking tricks to show Holmes's process of thought, and the going back to show what was going on in previous scenes, and Holmes's first pursuit of Irene Adler was *great.* But it was all too uneven for me, and even the heights failed to rise to what I'd hoped for.