I've always been a bit of a sucker for a period drama generally, but the quality of this one was particularly impressive. Visually, it was convincing and beautiful. Aesthetics is, I think, one very important area of film where we can fail to give credit when it's due, except of course when there's something weird and wacky going on with it, or when it becomes a deliberate statement (which is easily tiresome and pretentious - I'm thinking of some of the sort of artsy stuff I had to sit through when I did Film Studies). The designers of The King's Speech deserve some recognition for this.
The script and direction too were spot on, and did what they needed to. It maintained a sense of humour and a lightness of tone, despite its closeness and the sadness it dealt with. Perhaps most impressively, it wasn't really royalist at all. It made me pity a King, a sensation I'm far from used to outside of Shakespeare (incidentally, fitting references to Richard III, Othello, The Tempest and Macbeth cropped up). George didn't want to be a king, and should never have been one. Neither should his brother. Rather than blaming individuals, however, we saw the faults of the system that forces people in positions they can't cope with or simply don't want to be in.
Above all though, it was the acting that made this film. On all other counts, I think the mania about The King's Speech kept a lot of other fantastic films from achieving much-deserved recognition (for example, Christopher Nolan scandalously was not so much as nominated for Best Director with Inception), and it was partly my indignance on their account that prevented me from seeing this film earlier. Toy Story 3, True Grit, Inception, Alice in Wonderland, Harry Potter and the Deathly Hallows: Part 1, Burke and Hare, Four Lions, Tangled - all of these I loved. If I had decided the winners on my own, the Oscars 2010 would have looked something like this:
Best Director: Christopher Nolan - Inception
Best Actor: Colin Firth - The King's Speech
Best Actress: Hailee Steinfeld - True Grit
Best Supporting Actor: Geoffrey Rush - The King's Speech
Best Supporting Actress: Helena Bonham Carter - Alice in Wonderland (not for The King's Speech, which didn't make enough demands of her to merit an award)
Best Animated Film: Toy Story 3
Best Original Screenplay: Chris Morris - Four Lions
Best Adapted Screenplay: Coen Brothers - True Grit
Best Music: Randy Newman - Toy Story 3
Best Cinematography: Inception
Best Costume Design: Alice in Wonderland
Best Make-Up: The Black Swan
Best Visual Effects: Inception
As for the other categories, I don't feel as qualified to comment on documentaries and short films which I didn't really see, and "Best Film" is just such a stupid category that it's not worth bothering to try answering.