Welcome to Toronto!
Once you are here, I suggest visiting prospective areas to see if you'd feel comfortable living there. Toronto doesn't suffer from extreme ghettoization like some US cities do; sure there are areas that are more or less gentrified, more expensive, or more "gritty", but everyone has their own preference regarding the type of neighbourhood they like to live in.
We can't all live in Yorkville or Rosedale, and frankly, many of us would rather not even if we had the means. I think it's unfair to further stigmatize certain neighbourhoods that may have a less than stellar rep (fairly or unfairly) because it insults the honest, hard-working majority in each of these areas, and it perpetuates the subconscious idea that crime is acceptable and normal in one area and horrifying a few streets away in a "nicer" area. Finally, things change, and often quickly. Nothing is more frustrating that hearing people repeating outdated negative comments about an area that was perhaps undesirable 10 years ago, but has changed immensely in that time.
Rather than focus on crime, which can happen anywhere, I'd focus on finding a place where you can commute between work and home with the least hassle. The ordeal of your daily commute from North York to downtown, say, would probably far outweigh the other considerations.