We usually stay at the Royal York, which is now part of the Fairmont chain--very close to Union Station, a main subway hub. We have stayed at the Delta Chelsea Inn and Le Meridien King Edward--both are quite good and within a quick walk of the subway. The Delta Chelsea Inn is very child-friendly, has a big pool and a 4- story heated waterslide. (The Delta is just down the street from Barberian's, a wonderful old-style steakhouse--go there if you want to splurge and love big steaks). Also stayed at the Toronto Downtown Marriott Eaton Centre, which is connected the the Eaton Centre mall--and a subway station. I've also heard good things about the Novotel Toronto Centre, which looking at the map, appears to be a bit of a hike (5-10 min.?) to the closest subway.