I love (almost) everything David Lynch. Lost Highway is also one of my favorites. I remember seeing Eraserhead as a kid not long after it was released, and while not understanding much, I recognized the utter genius of what I had just witnessed with a strong desire to see it again.
The thing that no one seems to mention is that aside from his other influence on movies, TV and culture, Lynch forever changed sound design. After the post industrial soundtracks of his early films (and even shorts before EraserHead) many films adopted his droning and style of sound design that often stood in for incidental music score.
Twin Peaks was a style of TV that didn't exist before Lynch. The network execs didn't understand it and were constantly after him to solve the mystery. He protested that once the audience knew who killed Laura Palmer, no one would watch. He eventually acquiesced and the show indeed went downhill. Years later however the aesthetic payed off for ABC with Lost.
Another fact not often stated was that Mel Brooks is the one responsible for David's far flung impact on the world.
Brooks needed a director for a black and white film he was about to produce that he wanted to keep his name off, since he felt the world wouldn't take a drama, Elephant Man, seriously from a comedy director. He tapped Lynch to helm the project after seeing EraserHead, since it was a Black and white feature.
Without Brooks, Lynch may very well have been relegated to the art house scene or never heard from again, save for "painting" pictures with rotting meat.
As far as Dune, if one looks past the defects in the visual effects, (visible matte lines in the composites) and the off kilter performance of then newcomer Kyle MacLachlan, the film is brilliant and visionary in a way that makes Star Wars (years later Lucas digitally cleaned up its far better mattes) seem Closer to a cartoon version Dune's themes. The longer director's cut is worth seeing, especially with a friend who has read the Herbert books to discipher the language and fill in some of the back story.