The area you should plan to live in, should depend entire on where you expect to find work. That is, if you're going to work.
If you want access to downtown, but you wish to live somewhere less hectic and less expensive, then you might look at Brampton, somewhere near on its train GO stations. The GO train takes you to downtown Toronto in just over 30 minutes. The cost of living around Brampton is less than most places around the GTA.
The school is always a bit of a toss up.
Another question is, must it be Toronto? There are other places that are more friendly. Ottawa, Halifax, heck even Montreal. That's my personal opinion though. Toronto is definitely a happening place. But good grief it's crowded, and it's taking a toll on people. Personally, I vouch for Ottawa. It's got an economy still, and it's less stressful. It's better for raising kids in my opinion.