This post, on The Dollar Stretcher (excellent website for thrifty types), does a better job than I have in explaining why I think it's pretty much a good idea for almost everyone to pay off their mortgages.
The tax write off is not enough motivation since you only get 25-30% of your interest money back. In the long run, paying off early, even just over paying a bit each month, can save you more than 25-30% of that interest.
And think about what you could do with that money WITHOUT a mortgage payment. Save it. Pay off other debt. Improve you health insurance. Travel. Buy better food. Quit your job in a huff. Avoid losing your house if you lose your job. Less debt means you are less of a wage-slave.
So, that sort of logic is why I'm saving saving saving and hope to buy my next home without a mortgage. If I pay cash, I'll save a TON on interest. I already did that by paying cash for the car. My interest cost was exactly $0.00. Nice.
According to an online interest calculator, if I'd gotten a 4 year loan at 5% interest I would have paid nearly $2000.00 in interest. Instead, that money is in the bank. I also paid no loan fees or costs.
I should look back at my old mortgage papers and see what my closing costs were. I know the interest, if I paid the loan off in the 30 years with no over payments or pre-payments, would have been pretty much 2 times the cost of the house...yikes.
End of today's rant.