Everyone and their uncle has posted their impressions about the film, so I guess I should do that as well XD
I am actually one of those canon purists, so I didn't like any deviations from the book, and there were a lot of those. I guess I should have just viewed the film as a separate entity from the book, maybe that way I would have enjoyed it more. But since I didn't, most of the time I was just sitting there being butthurt about how they changed everything.
I suppose what bothered me the most was how everything seemed to be so calculated and commercialised - some kid appeal with bunnies and slapstick humour (bird poop in Radagast's hair, really now), some fanservice for the ladies (Fili and Kili, and I bet they were made hot because in the end they die and that will also get some feels from the audience - nobody would care if ugly dwarves died), and fanservice for guys in form of fighting and action (there was not that much action in the book, and there was no Pale Orc or anything, but I suppose the Hollywood bosses figured people won't be able to relate to things if there is no arch-enemy).
And of course the fact that there will be 3 films already suggests that they intend to milk the franchise for what it is worth. I bet there will be like 3 kinds of DVD sets in the end, too.
Well, never mind that, let's get back to the actual film. I also didn't like how they made the elves seem like the bad guys. Sure, they needed some way to explain why Thorin was not a big fan of elves to show that there was some complex history between elves and dwarves, but not like that. Elves are supposed to be Good People, so I really didn't like that bit where Thranduil just looks on the dwarves whose home just got destroyed and then goes away. And what was he doing there in the first place, did he come along to watch dwarves roast in dragon fire? And later at Elrond's it was all wrong, too - in the book Elrond didn't really approve of the quest, but he still helped them and gave them food and stuff, but here dwarves had to sneak out of Rivendell, while Elrond seemed to want to delay them.
BTW, I never liked Bilbo in the book, but here he is annoying. Well, not he himself, but the fact that the film creators are constantly trying to show how speshul Bilbo is. In canon, for example, Thorin and Gandalf's swords are also supposed to glow blue, but they don't in the film - only Bilbo's dagger does because Bilbo is omg so special. And don't even get me started on the part where he jumps in to defend unconscious Thorin from orcs, what the hell was that. And Thorin giving Bilbo a hug, that seemed so out of character for Thorin...
Oh, and while we are on the subject of orcs, why did all the goblins look like bad caricatures? Ok, they are not supposed to be pretty, but they looked grotesque and fake like characters from a video game, I could not take them seriously at all. And the goblin kind was disgusting.
And the wargs looked really fake too.
But I did like the landscapes and the music.