Here's my order:
1. Mulholland Dr.
2. Blue Velvet
3. Fire Walk with Me
4. Lost Highway
5. The Straight Story
I know some might find the omission of Eraserhead egregious, but I've only watched it one time and never felt compelled to watch it again.
Mulholland and Lost Highway are my faves, I like his psychological mind-benders and they’re just so seductive with the dreamy visuals and music.
They also don’t have really gross-out stuff like the exposed brains in Wild At Heart, FWWM and Blue Velvet, and 90% of Eraserhead - which is puke-inducingly repulsive on several occasions. All masterpieces, but I just don’t love them as much as his later features, which I can practically watch on repeat.
His magnum opus, however, is Twin Peaks Season 3. I still can’t believe we actually got that, and that it was so incredible. I suspect it will be Lynch’s swansong.
You have summed up my favorite Lynch films with your Top 5. I can't put them in order though I will say Mulholland Dr. is my favorite. All are 10/10 for me.
I really like his other films but those five are the cream of the crop (no offense to Wild At Heart, Elephant Man, Inland Empire or Eraserhead fans).
And of course Twin Peaks is right up there with the films.