Look up the amortization for a 15 year mortgage and pay off your house at least that quickly if not sooner. That is a better investment than a 401K IMHO.
That will build real equity in your house in case you want to trade it in (sell it) for another at some point in your life.
30 year mortgages are making more money for the banks and mortgage investors. You might as well keep some of that interest money since you don't have any cash flow problems now.