Here is my list of scenes from the book missing in the movie:
1. No Dursley goodbye, with extra wizards and witches as security. Especially, no Dudley "'thanks.'" DVD will apparently have a cut scene of this. Doesn't affect the plot, though.
2. No Harry's birthday party, and Ginny's birthday gift, and Ron (not George) coming upon the scene. Not mentioned here nor in Movie 6 that they've broken up, so she can't be used as hostage. They weren't really "seeing each other" in Movie 6 anyway. Doesn't affect plot, except possibly the epilogue.
3. No Viktor Krum at the wedding (Fleur invited him) discussing Xenophilius's pendant and why anyone should be a famous Quidditch player when all the best girls are taken.
4. Not enough discussion about Dumbledore's past at the wedding. More might be in 7-2, when Hermione starts reading the book. Harry's wavering trust in Dumbledore is a major plot point in the book, though perhaps it's not all that important, until the late King's Cross scene. The book does contain large amounts of verbage directly from The Daily Prophet, which won't make for good movie-watching. Could have made it a talk-show-style vignette, though.
5. No torn letter and photo in Sirius's room.
6. No longer narrative by Kreacher about the locket, nor how Grimmauld and Kreacher are Harry's property.
7. No Lupin story at Grimmauld, with his doubts about his new family, how he later does the right thing and thanks Harry for it over Potterwatch. During this story, Harry learns that former MoM Scrimgeour fought to his end not to reveal where Harry was. without it, we don't know which side he's on.
8. Did Polyjuice Harry take Moody's eye?
9. No memorial to Harry and Potters at Godric's Hollow. The Potter's house should have been charmed to look like a regular house until a wizard looked closer to see the unfixable damage to it. Plus there should have been some magical graffiti there urging Harry on. There is also a memorial in the town square (war heroes in Muggles' eyes) that changes for wizards to a Potter memorial. Easy addition.
10. We didn't see the Dumbledore's, Kendra and Arianna's, graves in the Godric Hollow graveyard. He learns his sister had died at a young age.
11. No LV in Godric's Hollow almost catching H&H.
12. No recollection by LV, seen by Harry, of the Potter murders.
13. No portrait of former Headmaster Phineus Nigellus Black, who can flit between this portrait and the one in the Headmaster's Office. He tells someone at Hogwarts that H&H are in the Forest of Dean. Revealed later in the book exactly who, but now it's going to be a lot tougher, unless the two-way mirror will be used for this.
14. I'd like to have heard, after Ron destroys the locket, Harry say, "Ron, that wasn't me." And Ron replying, "I know. It was me."
15. No overhearing of Dean Thomas, Ted Tonks, Griphook, and a second goblin (can't remember the name offhand) about the fake Sword of Gryffindor currently in the LeStranges vault.
16. Ron tells them not to use the name Voldemort, as this is how he and the Death Eaters find those who are not afraid to use his name. That's how Xenophilius (lover of the unknown and foreign -- nice touch) calls the Death Eaters to his house. That's how they are supposed to be caught by Death Eaters later. That's how they were almost caught in London by Death Eaters earlier.
17. No mural about friendship on Luna's wall.
18. No new Quibbler edition with stories against Harry.
19. No escape plan that exonerates Xenophilius, already noted earlier
20. Bellatrix is righfully concerned about the Sword of Gryffindor, and how she is scared that it was taken out of her vault. We'll find out early in Movie 7-2 why.
21. I didn't hear Griphook announcing it was a fake. Nor that Harry told him to say so. Important, IMO, to the plot, or at least to the understanding. H&H&R should have reason to suspect something is in that vault.
22. No Wormtail death by his own silver hand, though in Movie 4, he was not warned not let his loyalty waver.
23. No Dean Thomas in the Malfoy dungeon.
24. No Luna talk at Dobby's funeral.
Most are not extraneous. Only a few should be there instead of an awkward dancing scene which should have ended with, "Hermione, I love you, but I don't want you to bear my children." "Same here." Or something of that sort.