Advice about where to live (Toronto)

Hi there. Is anyone able to give me some insight about where the best places to live are in Toronto for young professionals? Yonge-Eglinton has been mentioned, but I have very little to go on since I don't really know anyone in the city. I would want to be within the city and with easy access to downtown to get to work. I also won't have a car so it needs to be well connected to public transport - any insight would be gratefully received!