Right now you can transfer $10,000,000 individually Federal Estate Tax free by gift or Will, $20,000,000 for married couples. In fact you can leave or gift unlimited property to your spouse with no current Federal Estate or gift taxes. Be careful though because even if you avoid Federal Estate and gift taxes you may still incur State Estate and/or inheritance taxes.
If your Will passes certain appreciated real and/or personal property (such as stocks and bonds) to your heirs, they may receive these at the then “stepped-up” market value, thereby possibly avoiding capital gain taxes on a subsequent sale.
For proper planning you should also strongly consider a Power of Attorney so that trusted persons can carry on for you if you are out of reach or incapacitated. Otherwise, your family might need to petition the Courts to appoint a Guardian for you.
You should also consider a Healthcare Proxy (so that your family and/or friends can obtain medical information if you are hospitalized), and so that you can create a “do not resuscitate” directive if you become brain dead or without a chance of recovery.
Also, consider that possibly a few simple transfers of interests in Corporations, Partnerships or LLCs can save you a bundle in taxes.