Justifying federal funding
Most of the answers coming in have been "no," and often "no, but…." I'm inclined to agree with everyone that the system we have is pretty good. The NSF is meant to fund basic research, as is NIH funding. Private industry does a fine job of funding applied research, but public grants are what gives private funders the ideas about what to do. The public elects people who allocate a block of funds to various research areas. Professional scientists who know what is happening in the field then make decisions about which projects to fund. The public sets priorities, the professionals make sure the money doesn't get wasted on boondoggles.
As for the "but" part, a persistent complaint about the creationism debate is that scientists don't do enough to explain what they do. It took ten years for the scientific consensus behind anthropogenic climate change to filter out to the public. As John Lynch points out, the NSF's regular surveys on public understanding of science show that people don't know simple things.
And while that's an argument against giving the public veto power over funding, it's a strong argument for requiring scientists to spend some percentage of their funded time on public education and outreach. Not on dry lectures that happen to be open to the public, but participating in a forum like Cafe Scientifique, or publishing an article on their work in a popular magazine.
Or maybe setting up a blog to discuss their research and the life of a scientist.