Built To Last
In a conversation between Steve Jobs and Ed Catmull, Co-Founder of Pixar, Steve said, "The devices I make will end up in a landfill, the movies you make will last forever." A powerful statement considering Jobs accomplished extraordinary things in his lifetime.
But it's true, there are things we can create that are temporal while others last years after we pass. The most immediate and valuable place to expend your energy into something that lasts is your family. Children and grandchildren.
If that was all you did, it should be vastly fulfilling. But if you want your work, your ideas to mean something after you're gone, the best way to guarantee it is do something for others. Create, write, produce timeless things that others will find valuable years from now.