The thing I always tell people about Moby Dick is that the beginning is lighthearted fun, the ending is amazing, and the middle is (to be blunt) quite dull. I think most people who make it to the end love the book, but getting there is a chore because Melville spends a great deal of time either talking about minutia of the whaling trade, or going off onto tangents almost in a stream of consciousness fashion that seem to have very little to do with the narrative (he devotes an entire chapter to telling why the color white is frightening, and another to listing characters from legend whom he identifies as whalers (Perseus I can see, but St. George?)). The language is gloriously poetic in places, but other times it rambles almost aimlessly and feels very convoluted and self-indulgent, even by 19th century standards. (Yes, I know these are qualities that the book's devotees hold dear, but they're also the reason that so many people never finish the thing. Might as well be honest about it.)
At the end, it's extremely disturbing getting into Ahab's head and understanding what makes him tick-disturbing because it's present in all of us, an instrinsic part of the human condition: his rage at not being God. Ahab is pride incarnate, with all the hatred that comes with it. (The story of Jonah, sermonized in the beginning, is ultimately one of the need for humility before God, with the whale as God's agent. And it's important that Jonah's sin is not merely disobedience but a refusal to go on a mission of mercy.). I felt unsettled for a long time after I read this, because it demonstrates what a short jump it is between a classically Satanic villain (a being of total pride and hate waging an all-destructive and ultimately futile war on God, and luring all others to follow him to damnation) to the modern concept of the existentialist hero, fighting bravely against hopeless odds. Seen through his own eyes, Ahab is genuinely heroic--and then the reader has to step back and realize that on the contrary, hatred has all but consumed Ahab's soul, leaving the Rachel without help and leading his crew to death for his own pride's sake. If to understand is to approve, the reader who now understands Ahab is left asking, "Good God, what kind of person am I?" Today we tend to view pride as a virtue rather than a vice; what does that make any of us?
Needless to say, there's a lot there. It wasn't until years after I'd read the book that I'd sorted it out enough in my mind to feel that I finally "got it," and I'm still in the process of getting it. Everything in Moby Dick is a symbol, and I suppose that no two people completely agree on what the symbols represent (Melville surely wanted a degree of ambiguity, anyway). Here are my own opinions on what it all means: (spoiler warning)
The whale represents God.
The crew is mankind.
Queequeg, Dagoo, and Tashtego are the pagan nations of the Earth, willing to literally worship Ahab.
Starbuck is Christendom.
Ishmael and the rest of the crew are godless men of no religion, whose anchorless wills are overwhelmed by Ahab's own.
Elijah is a prophet.
Ahab is the Antichrist.
Fedallah is Satan, and his attendants are demons.
Even though Queequeg is one of the pagans, it is through his seeming death and resurrection midway through the novel that Ishmael lives--because of the coffin. And Starbuck, innocent of any crime, goes down with the ship anyway (giving Ahab pause, just before his own death, to essentially stop and say in horror, "What have I done?")
I'm not sure what Pip represents.
If you're buying a paperback, I'd recommend the Tor edition, (ISBN 0812543076) just because I think it's got a very nice cover painting, something publishers often don't bother with when reprinting a "classic."