I personally stay away from student housing, over priced and to management intensive, or any low rent areas ( Montreal St, Weller ave, the Heights etc.) Again although low rental has a higher return it is far more management intensive.
It really depends on your target market and how hands on you intend to be in your investment.
It also depends on your experience level. If you have managed people before and are well versed with the RTA then you should have a fairly good idea of what you want.
If you do not have any experience you may be way over your head starting with a 10 unit in the wrong part of town.
If you are new to the business I strongly recommend you join this forum:
http://myreinspace.com/f/