As far as security, many states govern how much you can charge and how the money is handled. Again, consult an attorney or work with an agent with rental experience.
I have also seen landlords to be very flexable with their tenants in these hard times and allow a few months rent to be higher so they don't have to come up with the full security deposit right away. When that amount is reached, rent falls to the agreed upon rate.
It it completely up to you as you are the landlord, just be aware of the houseing laws.
Wilkinson & Associates
Every area is different. I ususally charge one months rent and a deposit equal to two months rent. Always make sure you get a detailed rental application, proof of id and run their credit. You can also do a rential survey to see what the comparable rent is in the area.