The Deer Hunter is not a "Vietnam movie" or a "war movie." I wouldn't be any more likely to compare it to Apocalypse Now than Close Encounters. Apocalypse Now is episodic. It has some incredible sequences, but is a series of parts rather than a balanced whole. It contains great cinematography. Sheen is terrific. Brando, well... Cimino develops his characters to a much greater degree and I have much better feel for steel town Pennsylvania than I do for Vietnam after watching both. Frankly, I don't think the allegory in Apocalypse Now really works.
Lady Gaga is talented. However, her music isn't much different than other, contemporary schlockified, synthetic ear pollution. I'm just as likely to develop a headache from her stuff as any of her contemporaries.