You can start with some classics that have huge amounts of personality in the first-person narrator, such as The Adventures of Huckleberry Finn, Moby Dick, and Lolita. Very different narrators, all first person. They can give you an idea of why some of the best writers write at least sometimes in first person.
Well, that seems like a valid exercise of person tastes If I pick up a book and it has a prologue, there is a 90% chance I'll put it back on the shelf.
I'll second whoever said the Percy Jackson and the Olympians series by Rick Riordan. He does amazing first person. His writing is hilarious. Another series in first person by him is the Kane Chronicles. His newest series, The Heroes of Olympus isn't in first person, but he does third person and switches between the characters chapter to chapter and still does it amazingly.
The Dresden Files, by Jim Butcher, and Secret Sanction, by Brian Haig are both very well written first-person narratives. The first is Fantasy, the latter is a Legal Thriller. The Dresden Files would be my first choice, just because of how awesome the character is, and so with first person, you get all his awesome thoughts/comments -- which is the thing that makes or breaks first person: If you don't have an awesome character, than first person will be boring for your readers.
The last first-person book I read that was good was P.N. Elrod, Strahd: Memoirs of a Vampire. She writes a lot of vampire type of books, but this is actually one of the few I have read of hers, and it was quite good, though short. I recommend it if you are into medieval settings and vampires.
I just finished reading The Silver Linings Playbook by Matthew Quick, which I would highly recommend as an example of well-done first-person POV. The narrator/MC's voice is very unique and very consistent.
If you want to get the full first person narrator experience try to find some books with unreliable narrators. Just because they're telling the story, don't assume they know everything. I'd recommend Blithedale Romance by Hawthorne, if you feel like going fancy. I'd also recommend Special Topics in Calamity Physics by Marisha Pessl, and Cloud Atlas by David Mitchell-- especially for Frobisher's section of the book. Frobisher is one of my all time favorite narrative voices. I think Just a Couple of Days by Tony Vigorito is first person, too, but I can't remember, and it's currently packed. D:
