IF I SET UP A TRUST, IS A WILL ALSO REQUIRED?

Yes.  A will should be drafted in conjunction with your trust.  The will acts as a safety net.  If you forget to transfer your assets into your trust, then your will picks up those assets at the time of your death and transfers them into your trust allowing those assets to be distributed pursuant to the terms of your trust. A will drafted with a trust is called a pour-over-will. Assets you forget to place in your trust can pour from your will into your trust. Sometimes assets not transferred into your trust may require a Probate to be transferred into your trust, depending on their value. 

Note: The above is general information and you should consult with an attorney to answer your personal questions and to have your estate plan drafted.