I've got a huge soft spot for Sleeping Dogs. It's one of my favourite open-world games in recent years because it jettisoned a massive, sprawling world in favour of something a little tighter, but more polished in every regard. It's not just that the slightly smaller size of the game world (and it's still pretty big) allows for a more dense map, filled with things to see and do, but all of the various systems were mechanically excellent -- the combat, the driving, the stunts, all of it.
The Definitive Edition is nice and all, but there's really no reason to pay in double figures for a spit and a polish when you can pick up the original for £4.
It's a freakin steal at £4.