My favorites are:
Kensington Kitchen - Middle eastern -reasonably priced - 299 Wallace Ave.(South of Bloor & East of Spadina)
Myth - Greek Food -417 Danforth Ave
Sushi on Bloor - 515 Bloor St West
Yamato Japanese Restaurant - they cook right in front of you and its yummy! 24 Bellair Street (North of Bloor and West of Yonge)
Saigon Sister - Vietnamese - Affordable and yummy - 774 Yonge st. (South of Bloor)
As far as things to do:
Westin Habour hotel roof top restaurant (Tula) - If you can afford it you could eat there or you could go for coffee & dessert. You get a great view of the harbour front and lake. Just make sure you go at off hours (mid-afternoon during a weekday).
Royal ontario museum (ROM) - they have an ancient peru exhibit on now 'til Aug. 6 - Friday nights after 4pm are free.
Art gallery of Ontario (AGO)-it might still be under renovations. It would be open but wouldn’t have its normal setup.
Second city - currently playing “Tip of the Melting Iceberg”
Boat tour of the harbour & Toronto island start from Queen’s quay. There is a small amusement park on the island.
Eaton’s centre if you want to shop (Yonge & Dundas)
If you have time I suggest you go to Niagara-on-the-lake region and have a wine tour. Its about an hour and a half from Toronto by car.
As far a there being a lot of homeless, I would say for the size of the city there is less than you would find in other cities of the same size. I felt safe walking around and taking the subway alone after midnight.