Re-Fi and invest or pay off mortgage

[John P.]

With interest rates so low I am debating about re-fi'ing our home mortgage and buying some investment properties with the money.  For simplicity let's just say the home mortgage is paid off. Let's say house is worth $750k.  I believe I can get a 15 year re-fi mortgage at, or just under, 3%.  My income has me in phaseout for deductions so I do not get full value for tax deduction but still some benefit.  Am I being too conservative to just sit on a paid off house?  I could easily get $600k out of the home to invest and, most likely, have no problem paying the mortgage with the rents. I would love some insight/encouragement from you experts. What would you do?