Owl Addresses changed from year to year depending where the Trio was staying. With everything that has been stated previously I've attemped to list as much as is known:
HP books by year:
1a Mr. H. Potter, The Cupboard under the stairs, 4 Privet Drive, Little Whinging, SURREY.
1b Mr. H. Potter, The Smallest Bedroom, 4 Privet Drive, Little Whinging, SURREY.
1c Mr. H. Potter, Room 17, Railview Hotel, COKEWORTH.
1d Mr. H. Potter, The Floor, Hut-on-the-Rock, THE SEA.
1 Mr. R. Weasley, The Bedroom beneath Attic / The Fifth Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
1 Ms. G. Weasley, The First Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
1 Mr. F. Weasley, The Second Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
1 Mr. G. Weasley, The Second Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
1 Ms. P. Weasley, The Second Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
1 Ms. H. Granger, The Bedroom at the Top of the Stairs, 8 Heathgate, Hampstead Garden Suburb LONDON.
1 Mr. D. Malfoy, First Floor Bedroom on the Right, Malfoy Manor, Wiltshire.
2 Mr. H. Potter, Sharing the Bedroom beneath Attic / The Fifth Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
2 R. Weasley, Sharing the Bedroom beneath Attic / The Fifth Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
2 Ms. L. Lovegood, The Second Floor Bedroom, the Black Cylinder House, Ottery St. Catchpole, DEVON.
rest as in 1st year
3 Mr. H. Potter, The Smallest Bedroom, 4 Privet Drive, Little Whinging, SURREY.
3 / Mr. H. Potter, Room Number 11, The Leaky Cauldron, LONDON.
rest as in 2nd year
4 Mr. H. Potter, Sharing the Bedroom beneath Attic / The Fifth Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
4 Mr. R. Weasley, Sharing the Second Floor Bedroom / The Fifth Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
4 Ms. H. Granger, Sharing the First Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
4 Ms. G. Weasley, Sharing the First Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
rest as in 2nd year, except for Percy (graduated and moved out)
5 Mr. H. Potter, Sharing the Second Floor Bedroom, Number 12 Grimmauld Place, LONDON.
5 Mr. R. Weasley, Sharing the Second Floor Bedroom, Number 12 Grimmauld Place, LONDON.
5 Ms. H. Granger, Sharing the First Floor Bedroom, Number 12 Grimmauld Place, LONDON.
5 Ms. G. Weasley, Sharing the First Floor Bedroom, Number 12 Grimmauld Place, LONDON.
5 Mr. F. Weasley, Sharing the Third Floor Bedroom, Number 12 Grimmauld Place, LONDON.
5 Mr. G. Weasley, Sharing the Third Floor Bedroom, Number 12 Grimmauld Place, LONDON.
rest as in 4th year
6 same as 5th year, except for Fred & George (moved to Diagon Alley)
7 should be as 6th year, except Hermione would not have gotten a letter ("Mudblood" Satus)
other/pre HP Books (other Owl Addresses):
The Weasley Family, The Burrow, Ottery St. Catchpole, DEVON.
Mr. B. Weasley, The Third Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
Mr. C. Weasley, The Third Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
Mr. A. Weasley, The Fourth Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
Mr. M. Weasley, The Fourth Floor Bedroom, The Burrow, Ottery St. Catchpole, DEVON.
Mr. A. Weasley, Sharing the Third Floor Bedroom, Number 12 Grimmauld Place, LONDON. (during Book 5)
Mr. M. Weasley, Sharing the Third Floor Bedroom, Number 12 Grimmauld Place, LONDON. (during Book 5)
Mr. S. Snape, The Smallest Bedroom, 12 Spinner's End, MANCHESTER NORTH.
Mr. S. Black, The Third Floor Bedroom, Number 12 Grimmauld Place, LONDON.
Mr. R. Black, The Third Floor Bedroom, Number 12 Grimmauld Place, LONDON.
Hogwarts Faculty & Staff during the school-year:
(*: Floor unconfirmed, °: stated one same as classroom, in analogy to DADA and for references mentioned in the books)
Mr. A. Dumbledore, Headmaster's Office / Headmaster's Tower, Hogwarts, SCOTLAND.
Ms. M. McGonagall, Head of Gryffindor House's Office / Transfiguration Professor's Office / First Floor Office, Hogwarts, SCOTLAND.
Ms. M. McGonagall, Headmistress's Office / Headmaster's Tower, Hogwarts, SCOTLAND.
Mr. S. Snape, Head of Slytherin House's Office / Potions Professor's Office / Dungeon Office, Hogwarts, SCOTLAND.
Mr. S. Snape, Headmaster's Office / Headmaster's Tower, Hogwarts, SCOTLAND.
Mr. F. Flitwick, Head of Ravenclaw House's Office / Charms Professor's Office / Seventh Floor Office, Hogwarts, SCOTLAND.
Ms. P. Sprout, Head of Hufflepuff House's Office / Herbology Professor's Office / Greenhouse #? Office, Hogwarts, SCOTLAND.
Mr. C. Binns, History of Magic Professor's Office / Fourth Floor Office, Hogwarts, SCOTLAND.
Mr. H. Slughorn, Potions Professor's Office / Sixth Floor Office, Hogwarts, SCOTLAND. (formerly G. Merrythought's office)
Mr. R. Lupin, Defence Against the Dark Arts Professor's Office / Second Floor Office, Hogwarts, SCOTLAND.
Mr. A. Moody, Defence Against the Dark Arts Professor's Office / Second Floor Office, Hogwarts, SCOTLAND.
Mr. G. Lookhart, Defence Against the Dark Arts Professor's Office / Second Floor Office, Hogwarts, SCOTLAND.
Mr. Q. Quirrell, Defence Against the Dark Arts Professor's Office / Second Floor Office, Hogwarts, SCOTLAND.
Mr. D. Umbridge, Defence Against the Dark Arts Professor's Office / Second Floor Office, Hogwarts, SCOTLAND.
Ms. A. Carrow, Defence Against the Dark Arts Professor's Office / Second Floor Office, Hogwarts, SCOTLAND.
Ms. S. Trelawney, Divination Professor's Office / Seventh Floor Office, Hogwarts, SCOTLAND.
Mr. S. Vector, Arithmancy Professor's Office / Seventh Floor Office, Hogwarts, SCOTLAND. (*,°)
Ms. B. Babbling, Study of Ancient Runes Professor's Office / Sixth Floor Office, Hogwarts, SCOTLAND. (*,°)
Ms. C. Burbage, Muggle Studies Professor's Office / First Floor Office, Hogwarts, SCOTLAND. (*)
Ms. A. Carrow, Muggle Studies Professor's Office / First Floor Office, Hogwarts, SCOTLAND. (*)
Ms. A. Sinistra, Astronomy Professor's Office, Hogwarts, SCOTLAND.
Mr. S. Kettleburn, Care of Magical Creatures Professor's Office, Hogwarts, SCOTLAND.
Ms. W. Grubbly-Plank, Care of Magical Creatures Professor's Office, Hogwarts, SCOTLAND.
Ms. R. Hooch, Flight Instructor's Office, Hogwarts, SCOTLAND.
Ms. I. Pince, Librarian's Office / Third Floor Office, Hogwarts, SCOTLAND. (*,°)
Ms. P. Pomfrey, Matron's Office / Healing Wing Office, Hogwarts, SCOTLAND.
Mr. R. Hagrid, The Cabin on the Grounds, Hogwarts, SCOTLAND.
Mr. A. Filch, Caretaker's Office / Ground Floor Office, Hogwarts, SCOTLAND.
- - - Updated - - -
Diagon Alley / Knockturn Alley:
Amanuensis Quills, Diagon Alley North Side, LONDON.
Borgin and Burkes, 13B Knockturn Alley, LONDON.
Broomstix, Diagon Alley, LONDON.
Daily Prophet, (Next to 129b) Diagon Alley South Side, LONDON.
Eeylops Owl Emporium, 521 Diagon Alley North Side, LONDON.
Flourish and Blotts, Diagon Alley North Side, LONDON.
Floo-Pow, Diagon Alley, LONDON.
GalloLoans, 343 Diagon Alley South Side, LONDON.
Gambol and Japes Wizarding Joke Shop, (Next to 18a) Diagon Alley South Side, LONDON.
Gringotts Bank, Diagon Alley North Side, LONDON.
Magical Menagerie, Diagon Alley North Side, LONDON.
Merge ML Corporation Ltd., 9 Fretdend, LONDON.
Obscurus Books, 18a Diagon Alley South Side, LONDON.
Quality Quidditch Supplies, Diagon Alley North Side, LONDON.
Second-Hand Robes, (Next to 129b) Diagon Alley South Side, LONDON.
Scribbulus Writing Instruments, Diagon Alley, LONDON.
Slug & Jiggers Apothecary, Diagon Alley, LONDON.
Sugarplum's Sweets Shop, Diagon Alley, LONDON.
TerrorTours, 59 Diagon Alley, LONDON.
The Junk Shop, Diagon Alley South Side, LONDON.
The Ministry Press, Diagon Alley, LONDON.
Twilfitt and Tattings, Diagon Alley South Side, LONDON.
Whizz Hard Books, 129b Diagon Alley South Side, LONDON.
Wiseacre's Wizarding Equipment, Diagon Alley North Side, LONDON.
Mr. C. Crispe, Brews and Stews, Diagon Alley North Side, LONDON.
Mr. F. Fortescue, Florean Fortescue's Ice Cream Palour, Diagon Alley, LONDON.
Ms. Malkin, Madam Malkin's Robes For All Occasions, Diagon Alley North Side, LONDON.
Mr. Mulpepper, Mr. Mulpepper's Apothecary, Diagon Alley, LONDON.
Mr. Mulpepper, Mr. Mulpepper's Apothecary, Knockturn Alley, LONDON.
Mr. G. Olivanders, Olivanders, Diagon Alley South Side, LONDON.
Ms. Potage, Potage's Cauldron Shop, Diagon Alley North Side, LONDON.
Ms. Primpernelle, Madam Primpernelle's Beautifying Potions, 275 Diagon Alley, LONDON.
Mr. C. Quincey, Cranville Quincey's Magical Junkshop, Diagon Alley, LONDON.
Mr. F. & G. Weasley, Weasleys' Wizard Wheezes, 93 Diagon Alley, LONDON.
Mr. T. ?, Leaky Cauldron, Charing Cross Road, LONDON. (later owned by Ms. H. Longbottom née Abbott)
Hogsmeade:
Merge Publications, Office 323, Hogsmeade, SCOTLAND.
Olivanders, High Street, Hogsmeade, SCOTLAND.
Potage's Cauldron Shop, Hogsmeade, SCOTLAND.
Wiseacre's Wizarding Equipment, Hogsmeade, SCOTLAND.
Mr. A. Dumbledore, Hog's Head, Hogsmeade, SCOTLAND.
Mr. A. & Ms. Flume, Honeydukes Sweetshop,High Street, Hogsmeade, SCOTLAND.
Ms. R. Lee, Rosa Lee Teabag, High Street, Hogsmeade, SCOTLAND.
Ms. Puddifoot, Madam Puddifoot's Tea Shop, High Street, Hogsmeade, SCOTLAND.
Ms. Rosmerta, Three Broomsticks, High Street, Hogsmeade, SCOTLAND.
hope that helps ^^