In St. John's, most are within walking distance of the east end of downtown, where many of the bed-and-breakfast places are located. But this list is not comprehensive, so let me know if you want me to add a restaurant.
expensive but good:
While here in St. John's I don't go to restaurants much though, more to live music venues, though some such as The Gypsy Tea Room and The Casbah are restaurants which sometimes have live music and effectively act as bars in the later stages of their hours. I haven't caught live music at either one yet though.
I'll add tea and coffee shops at next edit. Some include Hava Java (Water St.), Perk-Up (Duckworth St., but I'm not sure if they are still there), Coffee and Company (Water Street), Mugshots (Water Street, they have a folk coffehouse Saturdays from 8 to 10:30 p.m.), Timothy's (across from Mile One Stadium), lots of Tim Hortons, and Wordplay (bookstore cafe). The Ship Inn also has coffee for $1.25 and allows smoking indoors, unlike the others, and the coffee is OK there if it is fresh. I don't think there is a dedicated cybercafe any more but The Classic Cafe (west site) and Wordplay may still have public Internet access as may the public and possibly university libraries, and as did My Other Office but I think they closed down (or moved?).
Olaf: "Beware deep-fried foods (if you have cholesterol problems, you'll go home in a casket: that's the warning of Patrick O'Flaherty who has written a caustic but fun book on Newfoundland called "Come Near at Your Peril"), and reconstituted milk (tinned milk is still a favourite here)."
Regarding that tea platter milk jug comment, I've never had anyone give me tinned condensed milk with water added to it (which is what reconstituted means). Some people use Carnation condensed milk in tea at home, from tradition, and prefer it to whole milk. Some places you might be offered a choice of fresh milk or condensed milk, some places they don't offer condensed milk (which some see as a minus) and some places they will serve condensed milk as the default but would provide fresh milk if asked.
If you like fish and chips, you can get some of the best here, but if concerned about your health perhaps make sure they drain it well, and don't have added beef gravy (sometimes along with vinegar, ketchup and loads of salt too) on your chips like some do. Also in the rural areas, or outports, a few (fewer these days) restaurants still use frozen pre-packaged breaded fish, for convenience, instead of the fresh stuff on their doorstep. Some might argue that this is a result of the cod moratorium but it was even more the case twenty years ago, well before the cod moratorium. [And with the increase in inshore stocks which I suspect when they reach a critical mass will undergo a biological catastrophe theory type transition towards the offshore too, such that I agree with governmental restrictions on inshore fishing until such a transition occurs, else it might not. Or consider that a bit of the chips (Blarney) if you like.]
But as more tourists and some locals returning from away to scout locations for the businesses they will be setting up, as soon as they establish experience, contacts and a nest egg away have demanded improvements, and with the good catches in the scientific monitoring Sentinel fisheries, enough for local use but not for international export, I would bet that fewer places are using prepackaged breaded fish these days. Oh, probably some locals always wanted a return to the pre-prepackaged breaded fish days of old. So ask the locals and they'll point you in the right direction.
There are various degrees of vegetarians ranging from vegan to lacto-ovo vegetarian, and also those who cannot rightly call themselves vegetarian, who are fishetarians (don't eat mammals or birds), which includes me for now, and chickenetarians (don't eat mammals). Such might want to ask questions such as do they use lard for deep fat frying or in pies (the term lard is animal fat, the term shortening is a little ambiguous but is generally animal fat or partly animal fat unless preceded by "vegetable oil"), has the dressing (stuffing) actually been baked inside or touching a bird, does the onion ring or zucchini batter have egg in it, or do they fry chicken in the same oil as the fish. A few places (including Chucky's ) are using vegetable oil for deep-frying, though some switching over have not learned to adjust the temperature properly, I believe deep frying of fish in vegetable oil requires a slightly higher temperature than doing it in lard. Oh, and also some places deep fry their cod tongues too much, they are ideally pan fried or deep fried only until still jelly-like in the middle for the sensuous texture. And if you sigh "coquilles St. Jacques" some will ask if you've been listening to Happy Girlfriend. Ouch, no flames, please. [Explanation: They used to cover David Byrne's Psycho Killer song but have broken up]
Olaf: "Most of the restaurants and pubs are either on Duckworth Street or Water Street (pubs and restaurants are especially thick around George Street which empties into Water Street)." Some restaurants are also in the area near Freshwater Road and Parade Street, Churchhill Square and various spots all over town, though many of these are the standard neighbourhood fish and chips and/or pizza places, but some are good.