That would be John Constantine/London, the city.
There is exactly one reason why there has not been an anthropomorphic incarnation of the city of London in Hellblazer (as far as I know): she would provide a stable, albeit dysfunctional and borderline abusive, romantic relationship for John, and the series would explode.
Nevertheless, in my heart of hearts I want her to exist and John to finally find his soulmate in her.
Day 02 - What was your very first ship?
Day 03 - A pairing that needs to happen now?
Day 04 - The pairing with the most chemistry?
Day 05 - The pairing with the least chemistry?
Day 06 - The best kiss?
Day 07 - The most heartbreaking scene?
Day 08 - The pairing with the most baggage?
Day 09 - The most believable relationship?
Day 10 - Why aren't these two married in real life?
Day 11 - What is your dream pairing?
Day 12 - Who had the best wedding?
Day 13 - What is your favorite television pairing?
Day 14 - What is your favorite book pairing?
Day 15 - What is your favorite real life pairing?
Day 16 - What is the absolute worst pairing?
Day 17 - A pairing you thought would never work out, but did?
Day 18 - What is the cutest pairing?
Day 19 - A pairing you've rooted for since the beginning?
Day 20 - The "can't stand the sexual tension anymore" pairing?
Day 21 - A pairing you like and no one else understands why?
Day 22 - A pairing you hate and no one else understands why?
Day 23 - A crazy love triangle/quadrilateral that worked out great?
Day 24 - A crazy love triangle/quadrilateral that worked out badly?
Day 25 - A pairing that was/would-be adorable, but could never work out?
Day 26 - A pairing that you hated and ended up loving?
Day 27 - A pairing that you loved and ended up hating?
Day 28 - A pairing that you will never understand?
Day 29 - What ship had the best proposal?
Day 30 - Your favorite ship forever and ever and ever?