1. Dirk from the Weetzie Bat books by Francesca Lia Block - I do love a punk rock boy with a heart of gold. Weetzie Bat gets most of the hype, but the Dirk-centric book in the series - Baby Be-Bop - is tied with Witch Baby as my favorite featuring those characters.
2. Simon from the Mortal Instruments series by Cassandra Clare - Full disclosure: I haven't read the third book in the series yet - I am currently on the waiting list for it at the public library. But I still love me some Simon. I liked him OK in the first book, but his development in the second book (which I found to be generally superior to the first, boding well for book three) brought him up to beloved status. He went from being your garden-variety wise-cracking indie geek boy best friend to a BAD-ASS wise-cracking indie geek boy best friend, and it was awesome.
3. Marcus Flutie in Sloppy Firsts and Second Helpings by Megan McCafferty - I wasn't crazy about the direction his character took in Charmed Thirds and I haven't read the fourth and fifth Jessica Darling books yet, but holy cow, I loved Marcus in the first two books. I don't think I would have had Jessica's willpower to resist him as long as she did.
4. Dexter from This Lullaby by Sarah Dessen - Sarah Dessen can craft a dreamy love interest like no one else, and Dexter is my personal favorite. Whether he's crashing through Remy's bedroom window or waggling a fork at her through his front door, he's completely adorable.
5. Nick from Nick and Norah's Infinite Playlist by David Levithan and Rachel Cohn - Does this even need an explanation? I mean, really? And can I take this opportunity to go on record as saying I was totally devastated that they didn't put the scene with the Pepsi machine in the movie? It was my favorite part.
As is usually the case when I make lists like this, I'm sure I'll start thinking of other good choices as soon as I post, but still - I think this is a pretty good slate of lovely boys. Don't you? :)