It's a good first step, but it's still putting all your eggs in the same basket. You need to diversify. Even if you want to keep bitcoins as an investment or to promote the system, you need to invest at least one out of each two bitcoins mined into a different portfolio. Be it gold, real estate, remunerated savings account, stocks, venture capitalism, more mining rigs, take your pick. And don't forget to give 10% to charities!