I had skipped The Unnamable, feeling it's not that long since I last read it, but it is comparatively short so I read it after Alexanderplatz. Strange that something so intensely experimental should also have so many funny lines.
What made it fresh is that about a year ago I read a study by Pascale Casanova that sought to show that Beckett, especially in his later writings, was not addressing existential angst but the literary project itself -- essentially, writing about writing. That's controversial, but it's certainly possible to read The Unnamable that way, and it makes it a different book.
Now I'm far into Karamazov, which meanders of course but is compulsively readable. And thank god at 800 pages.