Manned space travel is a wate of money and the ISS is a political stunt. Having said that, I work in astrophysics, but I keep my butt firmly situated on the ground studying subatomic particles which come from the sun (and various other places). Things like the Hubble Telescope, the COBE satelite (which just won the Nobel prize), and other unmanned space probes are doing teriffic science and every penny on these has been well spent.
Some people seem to think that the worls resources are going to dry up and everything will end ala Thomas Malthus when the population reaches a certain level. Going into space is a completely worthless way of solving this problem. What we need to do is work to control our population and use our resources more wisely. If you have some bugs that live in a bottle and they double in population every day, even if you move half of them to a new bottle when the first is halfway full they'll still only last two days before both bottles are full instead of one. That's hardly a solution.