Linda's Place, at 9 Mile and Harper in SCS, hands down!
The place hasn't been updated in decades so it doesn't smell like corporate greedy stink, just good ol' fashioned decor (which funny enough, the owner Linda has an obsession with Coca Cola and decorated the restaurant to reflect such).
Bread Pudding = HELLZ YEAH.
Also, not only are the goth friendly, but pretty much no preppy people go there, which is a bonus.
You get to know the waitresses on a first name basis.
AND...you can go there, with change, get JUST coffee and there is NO limit. You can sit there for three, four, even five hours if you want with JUST coffee AND they keep it piping hot! Infinite refills, no hassle, no feeling rushed, no need to buy actual food...for like two dollars. Also, they're 24 hours and the most fun place to go when you're drunk. Great for people watching and being creepy.