PMI = Private Mortgage Insurance.

Many places offer "80/10/10" or even "80/15/5" loans. First mortgage is 80% of the principal, 2nd mortgage (at a higher rate) for 10% or 15% of the principal, and you make a 10% or 5% down payment. You won't have to pay PMI and the interest on the 2nd mortgage is deductable. (And I think there are even places that offer 0% down mortgages, or used to. I'd be scared of that unless I really understood the costs.)

80/10/10 or 80/15/5 is a great system for those who can't or don't want to put 20% down.

I agree with the desire to pay things off early (I'm paying off my 30 year mortgage in 20 years), though there are good arguments (like those given by Ben long ago) that it's a mistake to have too much money tied up in your home (e.g. it's hard/expensive to get it out).

Cheers,
Scott.