I've read all the books three times and I'm fairly obsessive about the details.

The Deathly Hallows part 1 movie seemed to rush through things so quickly that people who didn't read the books will have missed many important points -- it ended 2/3 of the way through the final book, leaving only 1/3 for the last movie.    Ron's emo fit seems out of place considering it happens like 5 minutes after they escape the Ministry of Magic, in the movie.

Many important things were left out:

Kreacher's Tale was eviscerated.   Everything that sort of redeemed Kreacher was redacted.   Lupin's visit to Grimmauld Place was redacted.

Goblin's Revenge -- here in the book you learn that Ginny attempted to steal the Sword of Gryffindor from Snape's office, and the punishment was rather lax.  We also learn from Griphook that Snape transferred a fake sword to Gringotts.   This drops keeps Snape's allegiance in doubt despite his killing Dumbledore at the end of the previous movie.

That entire chapter was cut out of the movie.  Now Snape's being a good guy will be a totally random deus ex machina in the last movie, because all attempts to foreshadow it were removed from the first part.

 Radio -- It was funny in the book, but just dull chatter in the movie.  It was associated with the resistance in the book, but just boring in the movie.   The whole idea that they have to dig a little deeper to get the truth rather than listening to the official establishment radio -- gone.   Other watering-down of the subversiveness consisted of cutting out parts about Fudge and Scrimgeour.

Everything about Phineas Nigellus was redacted, so there's no way for H,H,&R to know that Dumbledore used the sword to break the ring, and no way for Snape to find them in the Silver Doe chapter.

An even more crucial point -- the part where Harry asks Griphook to say the real sword is a fake.  That was completely redacted.    If they didn't lead Bellatrix to believe the sword was a fake, then Voldemort would know prematurely what they were up to, and the whole plot would fall apart since they wouldn't have time to plan the Gringotts break-in before Voldemort discovered his missing horcruxes.

Also, going to the Wedding and Godric's Hollow without polyjuice potion was really, really stupid.  That's not the way it happened in the book.

 All references to food during their time in the wilderness were cut.   Hermione going to muggle grocery stores in the invisibility cloak, taking stuff, and leaving some money behind, etc.   All that was cut.   Ron doesn't seem to have any motivation to go emo besides 5 minutes wearing the necklace, in the movie.

Kreacher's Tale and Goblin's Revenge were two of the best parts of the book, so I'm disappointed they got cut out of the movie.