For numbers of deer, I would suggest heading to the fields behind Humber College - North Campus located at Hwy. 27 and Humberview. There is a resident herd of approximately 7-8 deer in the valley and they love to eat the grass first thing in the am through the fall and winter. There are also occasional transient coyotes that pass through, but as I mentioned they only appear occasionally.
Other areas of the City that I've seen deer in include the Rouge Valley at both the Glen Rouge Campground on the north side of Hwy. 2, east of Port Union road or the massive hiking areas around the old Glen Rouge Ski Hill. This area is also home to several coyote families and one can often see and hear them in the evening as they search for dinner. Be aware, as well, that in the spring this area has also been known to have the occasional black bear pass through as they follow the river flows south to look for food such as berries. This is a rare phenomenon, but it does occur from time to time.
The Scarborough Bluffs also have a small population that spend time in the thick foliage on the hills that are at the foot of the Eastern portion of the Bluffs. Once again, there is the occasional coyote that will transit through this area. Foxes are numerous in this area as well, so keep your eyes peeled. One must exercise caution if departing the lower bluffs area at both twilight and night as there are usually animals found either bouding accross or beside the road which is the sole access point to the Scarborough Bluffs.
There is also a herd in the Kortright Conservation area, along with a family of coyotes. They are tough to find during the day, but if you spend some time in the deep forests you'll often catch glimpses of them as they flee. The best time to see any deer is usually the very early morning or in the evening, which doesn't fit well with Kortright as their hours don't encompass those times.
There are also occasional sightings of deer in the Don River Valley as far south as Eglinton Ave, and I believe someone here posted photos of them on this forum, just unsure of their location. The ones that are normally seen over on the Toronto Islands and Leslie St. Spit are ones that have usually swam over while wandering the waterfront through Eastern Toronto in the areas I mentioned above or swimming down the Humber River and over from there.