I really like New Roots and go there often mainly for pasties from the deli especially as it's so close to Sheffield uni - I'm always recommending it to friends. It specialises in Fairtrade stuff and also has fruit and veg (not from halfway across the world) and some books, hand made cards and toiletries as well. They also run a charity to put up destitute asylum seekers and have a donation box for that, as well as petitions for good causes on the counter. It's always bright and cheerful with posters and ethical cartoons (plus Calvin and Hobbes which is always good) and friendly staff! Their deli has some really tasty veggie/vegan pasties/wraps (not homemade but from nice veggie companies Forest foods and Saker) and flapjack/crumble snacks as well as a range of cakes which are only about 80p for a decent sized piece which always goes down a treat-some of them are always vegan,choc ornage being my favourite. They also have a fridge with some chilled veggie foods. The newest feature of the shop is the 'Speakeasy cafe' downstairs where you can take your pasty/cake to relax on a big sofa with a cd player and ethical magazines and a random assortment of books at your disposal as well,and a toilet out back. They do cheap teas including herb/fruit ones too (only about 40p!). Well worth a look however long you're in Sheffield for although it's not right in the city centre,it's out just past the University of Sheffield.
Cons: Not totally vegan, 'Cafe' room uses disposables