While this may seem slightly childish, I have to say both Holly Short as well as Artemis Fowl, from, well, the Artemis Fowl series. I've been reading Artemis Fowl since I was a child, and while the plots are short and simple - with appropriate and interesting twists - the characters, and their interactions between each other, are simply so enjoyable to read that the Artemis Fowl series places itself near the top of my favorite book series of all time. Just finished reading the last book, The Last Guardian, which came out recently, and I really just can't help but love both her and Artemis. I don't hardly ever feel love for characters like I do for these two, so even though it's not really a crush, it's pretty much the only way I can really relate to this topic, haha.
I'm actually feeling extremely depressed now after finishing the series. Another one of my favorite book series ended; more people I love added to the list of characters I will never have the pleasure of meeting again. And another world that could've been that isn't...They're but figments of my imagination, now.