There are far too many to mention so I'll just go through the most usual discs in my machine.
First, I have something of a christmas ritual. I like to watch Scrooge with Alastair Sim on Christmas Eve. Alastair's portrayal of Scrooge is absolutely spot on and I love the transition from grumbling old miser to clown meister.
Second, I occasionally have a Lord of The Rings weekend. I watch all three fims on consecutive nights. I am also re-reading the novel for the fourth time. Heavy going, but beautifully written.
Third, Every year, on May 25th, the date of it's original UK Cinema release, Star War IV A New Hope. A ground breaking film and a delight, especially for the nine year old kid who is still inside me.
Finally, I don't have it on DVD any more but when I had it on video, I would watch At the Earths Core with Peter Cushing and Doug McClure. It was an awful film then and still is, but when you're eight...