Worthwhile like Apollo say. Apollo worked, and put America into the history books for ever. What is NASA doing today? Paying $30 million a seat to the Russians for a ride to the ISS? Buying Russian made rocket engines for the ULA Atlas booster? Launching a few robot probes?
Are we getting our money's worth?
The only real history making mission left is a manned Mars mission. This is within today's technology. I've seen plans to send the assent stage to Mars, making a soft landing under remote control. Then sending a second one just in case something breaks. Then setting up a nuclear powered chemical plant to synthesize fuel for the return trip from Martian air, soil, and perhaps water. Then using five Space-X Falcon 9's to boost a Mars mission, crew capsule, and lander into orbit. Four man crew. Doable out of the current NASA budget. Within a few years.
This would be a history book mission. Why don't we do it?