Which property to pay off 1st?

[Jason E.]

I bought a few single family home rental properties this year.  They are all financed with 30 yr fixed rate loans with different interest rates of course.  I was wondering what factor should I consider on deciding which property I should apply my extra cash flow to pay off first??  Should I pay off the one with the highest interest rate or the one with the total interest paid over 30 years???