[quote=FormerSanDiegan]The only real way to figure the tax benefit for your situation is to look at your specific return. If you use turbo tax for example, you can remove the mortgage and property tax deductions (and maybe switch to standard deduction if you don;t have a lot of other deductions) take the difference and divide by 12.[/quote]

So I did that with my Turbo Tax, and for 2008 I would have not gotten about $812 in savings each month. My guess of $900 was not bad using the add them up, multiply by 34%, and divide by 12.