First off, Led Zeppelin is my favorite band of all times, so this may be a tad biased. I'll try and keep my opinion out of it.
Like the above review says, this is arguably Led's best album. The classic "Stairway to Heaven" was first released on this album, as well as "Black Dog." Black Dog is not as bad as the above review makes it sound. The so called "Grunting and Screeching" is barely noticeable, and when noticed, it doesn't sound sexual at all. Stairway to Heaven is (Probably) about a girl who dies and is ascending to heaven, although the purpose of the song is debated.
All over a great album. I would recommend it to anybody who loves the hard rock stuff.