As an American I know nothing of Canadian income tax laws...... but I do know something about US IRS taxes. Moisheh states that "US income tax laws are much different than Revenue Canada's . For instance upon death much of your estate will be taxed".
This statement is not correct. Your estate would be subject to tax by the IRS, but the current exemption before any tax kicks in is 5.43 million USD.
http://www.forbes.com/sites/ashleaebeling/2014/10/30/irs-announces-2015-estate-and-gift-tax-limits/
19 states also have some form of inheritance or estate tax, but none of them are snowbird states and most use the same exemption as the Federal government.
http://taxfoundation.org/blog/state-estate-and-inheritance-taxes-2014
So if your estate in CAD is not over 6.61 million (a $1.22 exchange rate) then the estate tax will not apply to you.