I still teach Allen Ginsberg's "Howl" (as opposed to someone else's "Howl?) in most poetry-writing and modern/contemporary American poetry courses I offer. It's a great example of a protest poem, and of "prophetic" poetic rhetoric going at least as far back as the Hebrew Bible. At the same time, it is squarely (not in the Beat sense of the term) in the tradition of Whitman and Jeffers, in the context of American poetry.
Not without its problems? Of course. As bad as Ginsberg and compatriots may have had it in the 1950s, others had it worse, so occasionally students, with good reason, ask, "Was it really all that bad?" Also, it is a dense poem. It asks patience. But that can be a good time.
I also like to teach the poem as one that gives the effect of a spontaneous "rant" but that is actually carefully crafted. And of course it is a crucial poem in the context of gay and lesbian literature.
I would cease teaching it if students seemed disengaged from it, but they still seem to find a purchase or two in the poem. They like to discuss it, critique it, and learn from it, at least on my campus.
In any event, here is a link to an interesting spectrum of views, from poets and others, on "Howl"