To start this off - I’m a Slytherin (and a Flinterforge, of course). Growing up I was surrounded by people who insisted I was a Ravenclaw, but I didn’t totally buy that.
For various reasons, I took the Pottermore sorting quiz three times (two in old Pottermore and one in current Pottermore), and got every result except Hufflepuff. Interestingly, the all-questions Pottermore quiz sorts me pretty easily into Slytherin, but certain combinations of questions will put me everywhere except Puff.
I’ve identified pretty confidently as a Slytherin ever since. (I’m also a huge fan of the Sorting Hat Chats Tumblr system, if any of you want to check that out.) Plus, I feel like the Slytherin ambition complements the Flinterforge inspiration as neatly as the Hufflepuff work ethic.
Edit: @Rimor, not exactly. I do want other people to contribute here.