Arg, I was hoping to do this before anyone really started posting, but I guess Dad beat me to it!
I started my reading by looking through all the supplementary material in my Norton Critical Edition, and I thought you guys might be interested in seeing what the critics had to say about MD when it was first published. So here's what we have to look forward to, according to the critics.
An anonymous critic from Parker's Journal says

Such a mass of information about the whale was probably never brought together in one book before, certainly never in a work of fiction. "Moby Dick," as a medium of information, cannot be found fault with. As a work of fiction it is liable to the objection which presents itself to all Melville's writings since "Typee." Typee was just perfect. In the attempt to make the rest better, and improve upon perfection, we think he runs into the grave error of giving us altogether too much for our money.

A different anonymous critic from the Boston Post, after declaring that "we have read nearly one half of this book," says

"The Whale" is not worth the money asked for it, either as a literary work or as a mass of printed paper. Few people would read it more than once...

And WIlliam Gilmore Simms has this promising note:

[Ahab's] ravings, and the ravings of some of the tributary characters, and the ravings of Mr. Melville himself, meant for eloquent declamation, are such as would justify a writ de lunatico against all the parties. 

But they're not all so dire. Eight years after Melville died and 48 years after MD was published, Archibald MacMechan had this to say:

 This book is at once the epic and the encyclopaedia of whaling. It is a monument to the honour of an extinct race of daring seamen; but it is a monument overgrown with the lichen of neglect. Those who will care to scrape away the moss may be few, but they will have their reward. To the class of gentlemen-adventurer, to those who love both books and free life under the wide and open sky, it must alway appeal.

That sounds more like it!