http://buildingequity.blogspot.com/2007/04/401k-vs-extra-mortgage-payment.html
"401K vs. Extra Mortgage Payment
If you find yourself with some excess income these days, you may be wondering whether you should put more money into your 401K or pay off your home mortgage faster.
Which is better?
From a purely financial perspective, if you have a low, fixed mortgage rate you are better off putting money into your 401K account. There are 2 reasons for this:
Any extra money you put into your house will have already been taxed. That means that your money has already lost 20% of its value before you are able to use it to pay down your mortgage. 401K contributions are pre-tax, meaning the money goes into your 401k account before any taxes are removed from your paycheck.
Your 401K will likely earn more than what you pay in interest on your house. Let's say your mortgage rate is 6%. Even at a conservative 8%, your 401k will out-earn what you pay in interest by 2%."
I know earning 8% on your 401K seem like a fantasy right now.