and by best I mean best or favourite.

I'm probably going to plump for the Death of Grass by John Christopher.
Easy to read, action packed and a far more realistic and scary apocalypse than any worn out trendy zombie tale.
http://en.wikipedia.org/wiki/The_Death_of_Grass

runners-up:
Let The Right One In by John Ajvide Lindqvist
beautiful vampire tale, a bit more bulky than the film but although I think the film was right to cut all that stuff out it never felt out of place or bloated in the book.

Overqualified by Joey Comeau
he writes the Softer World webcomic, this book is probably slightly better in concept than execution but it was still funny and sad in all the right places. A couple of the pieces near the start do however feel a little out of place and undermine the cracks that appear in the narrator/writers letters later on a wee bit.

and maybe some others I can't quite put my mental finger on at the moment.