I have so many that I love, but recently I was re-reading an older one called "What you don't surrender" by caffeinekitty which I think is only still available on ffnet. I just really like the characterization of the both of them and the slow burn is so good! Not to mention Izaya being a vengeful little bastard.
What are some of your favorite fics? Any pairing is welcome of course.
This is a Shizaya fanfic, but it is such a good story! It's called "The Cheap Imitation". It's a horror comedy. I love this story! I definitely recommend it!