One of the particulars of query letters I've seized upon (or thought about a lot, anyway) is comparative titles. You know, at the end there when you're like "MY BOOK is a contemporary fantasy, complete at 80k words. It would appeal to readers of Watership Down and Joseph Campbell's The Heroic Journey" (not a real sample). Or whatever. I've heard it's not a "requirement", but my understanding is its a good way to show you've read in your genre, have an audience in mind, etc. (these are the things I think about in lieu of "Dear Agent, I hope you lurve my book. Kisses! Me.")
When you invoke certain titles, I feel they're taken to mean something. If the only thing you can claim comparable is Alice in Wonderland, that better be some magnificent goddamn rabbit hole we're about to spelunk in, rife with poetics and symbols and absurdity. You must be aware of the shoes you are trying to fill, but you also must be aware of the other shoes in the closet. Using only Alice in Wonderland could suggest an ignorance of your genre, and who's writing and publishing in it today. Classics are classics for a reason, but when you want a professional to read your unpublished and shiny-as-you-can-make-it MS, you want to seem contemporarily adroit, I feel. A certain novice ignorance is to be expected, if this is your first time at the rodeo, but being a backwards Luddite is not. Nor is it desirable.
Even American Gods, at more than 10 years old, is too old (this is like ballet or child modeling). A great book, one of my favorites, oft lent and recommended, but another no go.
Lev Grossman's The Magicians is one I intend to try out, I think, when querying The Last Song. It's one of my more recent favorites, along with its sequel The Magician King. My other title (I've also apparently decided there need to be two?) I'm not sure of yet, as I poke around and see what else is coming out, and what others have written. I haven't produce something SO UNIQUE IT'S TOTALLY INCOMPARABLE, but it's "unique enough" that careful thought is required. Though I guess when it comes to writing and publishing books, careful thought should be a requirement.