In 1998 my wife and I bought our house in Cabbagetown for under $280K. The area was still pretty sketchy and my friends who'd bought in Milton or Pickering thought they'd get robbed when they visited. The neighbour's identical 5-bedroom three floor house just sold for $1 million. But it's not an investment unless you plan to sell, and I'm not going anywhere. Perhaps the kids will sell it when I croak.
Contrary to what builders and agents tell us, I do not think this phenenon is going to repeat today, where a $800K semi in Leaside that was $250K in 1996 is going to be worth $3 million in 2040, but we'll see.
Worst investment has to be a condo, as they're going up everywhere, maintenance fees will skyrocket as their window walls and mediocre build quality and materials reach their half lives in about 2030 and begin to fail.