Expenditure reduction could be more important than you have yet considered, and give you more future flexibility in your financial and emotional life: assuming you save the money not expended, which is its own learning experience, life practice and meditation.

You could have a twenty-year mortgage for about a percentage point less interest, and for a mere 250 dollars a month more payment, a mere 5% increase of your present monthly expenditure. By paying down the loan 10 years sooner, you may expend an additional $60,000 over 20 years paying the loan off, and also avoid later expending $180,000 for years 21 through 30, for a net reduction of about $120,000 at the end of 30 years (in the variable value "current-year" dollars).

You also could decide to own the house outright now, debt free, and save a mortgage expenditure of $1,500 a month for a reduction in expenditure of $540,000 over 30 years, and still have $200,000 cash reserves today.

Investing a stream of avoided mortgage payments of $1,500 a month -- $18,000 a year is equivalent to creating a 30-year investment/saving program. Assuming a not-so-great three percent interest on that program, you would have around $850,000 in hand at the end of year 30, in future (inflated) dollars. You could probably do better than that in investment return, and learn more along the way slowly, with less risk.

All of this points to $500,000 to being not much money, and the rest of your life activities and financial choices might have a far greater influence on your possibilities and life flexibility.

The money you could save in expenditure reduction, and equally importantly set aside for investing, might be a more powerful financial and emotionally freeing future for you than investing the $500,000 lump sum you have now.