Do you mean poetic with verse and meter? I'm thinking Goethe's Faust (Bayard Taylor's translation)—or the centre-piece in the book Pale Fire by Nabokov.
I guess I really mean books that are heavy on description. A description that sound almost poetic at times would be nice. I would love recommendations on some of the classics that writers here feel influence them the most or that they enjoyed.
Anything by Faulkner, Toni Morrison, or Cormac McCarthy... there are thousands of others, but those three are amongst the most "mainstream." You can always scan a list of Nobel and Pulitzer winners too. I ran that gamut in my formative years... most of them trend toward the literary side.
Nabokov is the first writer that came to mind. Some of McCarthy's descriptions in Blood Meridian are absolutely stunning. If you're looking for a good short story collection, I'll recommend James Joyce's The Dubliners; there is some beautiful writing in that collection.
The Picture of Dorian Gray. It's been a while since I read it, and I'm not sure I would call it poetic, but Oscar Wilde does make pretty with the words. It also happens to be a fantastic book. The Odyssey and The Illiad (the George Chapman translations) are actual epic poems. The language is beautiful, but it can be tough to read. It certainly was for me, and I have yet to actually read either book beyond the first 5 pages.
I've gotta recommend the book that I'm currently obsessed with, and that I've posted about like 5 times this week: The Road!
The Road is considered an Epic Lyrical -by some- and is a fine piece of Literature. - OP, The Road might be the most adult and contemporary book you can find. I'll go through my Libary -when I have a minute- and write a list of other works of fiction you should read if you are interested in the mixture of poetics, prose, and narrative.
The Age of Innocence by Edith Wharton. We are advised against purple prose in this modern, pragmatic age of literalism, but... what if you embrace it as you would a scandalous lover stealing into your fashionable New York apartment? Letting it in through the delivery door so that the servants do not see, up, up into the sanctum sanctorum of your mahogany panelled bedroom. Yes... you would have this novel is what you would have.