The Party Superstore was/is my absolute favourite London shop until it was bizarrely attacked and gutted during the summer London riots. They have been since adopted as a concession by the local Debenhams but you can still savour the full delights of the products and nonsense on line.
Rotorino is a lovely little Italian, intimate but casual spot in East London. The food is great and when the weather is good - having your wine and pasta outside is nice.
They mainly sell art and cultural theory books but they also have a good selection of small press and self-published zines. It’s a great place to browse and get ideas.
Small restaurant on Highbury Corner that started off focusing on (basically) posh kebabs, but which is now producing some of London's most innovative dishes, focused around unconventional meats, cuts, and breads. Not often you can eat incredible food while listening to heavy rock and metal, but Lee Tiernan has nailed a winning formula.