Where I live (Ontario, Canada) security deposits are illegal. Simplifies everything and levels the playing field. Key deposits are also illegal. Only thing a landlord can charge is rent (first and last up front) and its legally required to pay interest on the last month's rent (although good luck milking that from most landlords). No need for escrow since to get your last month's rent back you just don't pay your last month.

There are, of course, landlords who do not follow the law. As with drug dealers, pimps, and phone companies they generally prey on the less fortunate. Legal aid and the landlord-tenant tribunals keep busy.