Slytherin, without a doubt. Indeed, for over a decade I defaulted to Sytherin. I'm even one on Pottermore- I got to choose between Slytherin and Ravenclaw there. I've cosplayed as a random Slytherin multiple times over the years, and I have yarn for a Slytherin scarf waiting which was ordered before I was sorted here.
Here, Slytherin came up as my runner up spot, so I like to think I've learned what I needed to/was in a position to learn from and shift my drives that Slytherin enabled my access to, and that as an adult I have a subtly different set of drives, goals, and desires. Indeed, this is why on the main HOL forum my signature mentions my inner eagle beating out my inner snake this time.