I threw together a quick reference over notable events throughout the different movies while I was going through them earlier. Maybe these are handy for someone else. The main elements of each, chronologically...
Harry Potter - The Sorcerer's Stone (2001)
Introductions, the magic alley, Dudley and the snake, quidditch, the mirror of desires, killer chess and the teacher with two faces first introducing us to you-know-who.
Harry Potter 2 - The Chamber Of Secrets (2002)
The flying car, dreamy views, Myrtle the bathroom ghost, mandragoras, the vane author, Hermione going through some things, and finally the Basilisk and Tom Riddle in the flesh.
Harry Potter 3 - The Prisoner Of Azkaban (2004)
New castle with more of an isolated hillside feel, Sirius Black, dementors, a cat, a rat, a werewolf, a time warp and a hippogriph. And Voldemort is BACK.
Harry Potter 4 - The Goblet Of Fire (2005)
The blow-up aunt, worldcup terrorism, the great ball, uncertain love, Harry and Ron on bad terms, gillyweed, dragons, the multischool challenge, Mad-Eye and the death of a new character that seems meant to have always been there.
Harry Potter 5 - The Order Of The Phoenix (2007)
Politics, a refusal to accept Voldemort's return, the order - the resistance, Dumbledore's army, Dolores the new headmaster, Luna, prophecy at the Ministry of Mysterious Affairs and Sirius death.
Harry Potter 6 - The Half-Blood Prince (2009)
Draco, Snape, school again albeit with a darker tone, Horcruxes, one last adventure, Dumbledore's death and love, getting gray and grimy.
Harry Potter 7 - The Deathly Hallows: Part 1 (2010)
The world going dark, the chase, and wedding crash, infiltrating the ministry, Dumbledore's testament, wilderness, Hermione and Harry, hopelessness and the Horcrux that almost takes over.
Harry Potter 8 - The Deathly Hallows: Part 2 (2011)
Infiltrating Grimwalds, the final horcruxes - if you felt the count seemed wrong earlier it'll make sense now, Snape's true story, Nevil's heroic moment, wins, losses, Hogwarts great final defense and the deaths of the evil-doer's. An end; a new beginning.
Notice there's a new teacher of the dark arts with each and every one of these too! Some play central roles...