I can't believe no-one has replied! Depends what type of films you like really. Trust me, there's a Christmas film for every genre! Off the top of my head I would recommend -
The Holly and the Ivy Love, Actually Nativity! Virtually any version of A Christmas Carol / Scrooge Christmas Story The Shop Around The Corner Miracle On 34th Street (40s version) The Bishop's Wife Four Christmases Deck The Halls (Danny De Vito version).
Have a look at my profile at my reviews and lists....I only really review Christmas stuff!
It's A Wonderful Life Wizard of Oz Scrooged (Bill Murray) National Lampoon's Christmas Vacation Scrooge (Alistair Sim) Elf Blackadder's Christmas Carol The Muppet Christmas Carol The Grinch A Nightmare before Christmas