The Toronto Transit Commission (TTC) is Toronto's public transit system and unless you want to sweat the traffic it's your best way to get around. The system incorporates three subway lines, streetcars, buses, and an LRT extension.
The TTC will be most useful for you for the following:
1) If you are concentrating all or almost all of your visit on the downtown core. If this is the case don't even bother with a car. Streetcars and subways come often and will take you anywhere you want to go. And travelling this way will save the cost and hassle of parking. Plus driving downtown can be confusing and frustrating with all its "no left turn" intersections, one way streets, and the high volume of traffic.
2) If you are commuting to and from downtown frequently. No matter where you are staying, it will probably be just as easy, if not easier, to drive or bus to a subway station and then take a train downtown. The system is set up well for this and it is almost always a preferable option to driving downtown yourself. The exception would be if you plan to be returning after 2am, in which case the subway may have stopped running.
The park and drive option works well from Finch, York Mills, Yorkdale, Wilson, Keele, Islington, Kipling, Victoria Park, Warden, Kenedy, Lawrence East, and Ellesmere stations. There is also parking at Eglinton station. The parking fees vary a little but are generally between $3-$6. Free on weekends and evenings.
3) If you're non-downtown activities are centred on or near the subway lines. This would be anything along Yonge street, Bloor Avenue, The Danforth, Yorkdale Mall Area, and the Scarborough Town area.
However, the TTC becomes less convenient when you have to venture away from the subway lines away from downtown. Buses do run and will get you almost anywhere you want to go. However, they don't always come frequently (particularly outside of rush hours) and can make a simple trip more time consuming and draining than it's worth, particularly for long journeys. Example: travelling from north Scarborough to north Etobicoke will take you 30-45 minutes driving, but close to 2 hours on TTC.
Out here, away from the downtown core, driving is a lot less nerve wracking and parking much more plentiful. Thus, driving becomes a more viable action. When I say away from downtown I'm talking about the areas north of Bloor, West of the Don Valley Parkway, and East of Bathhurst. It seems that the further afield you go in these directions, the less frequent the buses become. With the exception of a few main routes.
Rates run as follows:
$2.75 single fare for an adult. This includes limitless transfers, meaning that you can almost always get wherever you are going for the price of one fare. You will soon learn that the system is configured in such a way that you can often go from one TTC vehicle to another without needing a transfer. But until you get the hang of this always ask for a transfer from the bus or streetcar driver just to be sure. In subway stations there are red automated transfer dispensers, usually located just inside the turnstiles.
Also of note: When riding buses or street cars you must have exact fare as drivers are unable to make change. At subway stations you can pay with inexact change at the turnstiles, though it's not always quick or convenient.
You can save a little on these fares by buying tokens at subway stations or tickets at various TTC kiosks around the city. When you buy them this way it will work out to $2.10, but you will have to buy several at once.
A day pass is $7.50, and is good value. It allows you to ride the TTC as often as you need or want to on the given day. Just to do the math, you would need to ride the TTC more three times or more during the day in order to make it worthwhile. This pass will also limit the hassle of transfers too, which is quite nice. You can get these at subway stations. Not worth the cost unless you will be using the TTC at least 42 times during your stay is the monthly metro pass at $93.50.
The system itself is well run. Stations are clean and the vehicles well-kept. A really nice touch is the streetcars that still zip along the streets south of Bloor.
The system is also fairly safe. They've gone out of their way to make it so. If concerned about safety you'll want to know the following information:
1) At subway stations wait at the clearly marked DWA areas. These areas are video monitored and have an emergency assistance apparatus on the wall where you can call for help. By both activating an alarm and/or talking to the security guards on duty via intercom.
On the end walls of the subway platforms are emergency levers that you can pull if someone were to fall onto the tracks. This lever, when pulled cuts all power to oncoming trains and summons the TTC emergency response team.
2) On board the actual subway, please note the yellow emergency assistance bar just below all the advertising. When touched, it stops the train and summons help.
3) On buses and after dark you can request to be dropped anywhere along the bus route. The idea being to eliminate long walks home late at night.
All this said, the subways feel safe and generally they are. So far they've been free of the levels of crime often associated with the subway systems of some other cities.
For more information on exact routes, times, links to other transit systems (i.e. neighbouring cities and GO Transit) check out the extremely thorough website at www.ttc.ca.