Having lived there for seven years, it's hard to narrow it down. It all depends what you feel like.
HAMBURGERS
Go to The Burger Factory on 1600 Regent Ave W and order the Factory Special. Great value and awesome burger. Better than VJs or Blondies in my opinion. And MUCH better than Salisbury House.
PIZZA
I agree with the above poster that Santa Lucia is a can't-miss.
ORIENTAL
If I was magically transported to Winnipeg for an hour, I would go to
Foon Hai. The chinese food is phenomenal here, most particularly the #170 spicy chicken soup. If you like spicy food, you will love this. 329 William Ave. It's downtown but there's free parking all around it.
I will make a bold statement and say if I could be transported anywhere in all of Canada for lunch, my top two choices would be: (1) Veal cutlet sandwich at California Sandwiches in Toronto and (2) #170 spicy chicken soup at Foon Hai in Winnipeg.
ITALIAN
DeLuca's is a great place for Italian food and a favourite lunch stop of mine when I lived there. It's that type of Italian food that tastes just like Nonna made it. Nice central location at 950 Portage Ave.
http://www.deluca.ca
DESSERT
Go to The Bridge Drive In on Jubilee Ave. Vanilla there is so good you could just get it plain and it would be awesome.
SIGHTSEEING
Bridge Drive In could qualify as a sight-see, but The Forks is nice also if you're just going in and out of the city.