Dr. Neil DeGrasse Tyson has been one of the most vocal supporters for NASA in the mainstream media. He has even testified before the Senate on the importance of NASA in space exploration and scientific advancement in general. NDGT is an excellent writer and speaker. He is probably the closest thing in astrophysics today to Carl Sagan. I've read a few of his books, which are fantastic. He just released a new one about a month ago, Space Chronicles, which sits at the top of my 'to read' list.
This video is a compilation of many of Dr. Tyson's statements on the subject, and it makes a very compelling case. The video was put together by Scrunchthethird on Youtube.
It is truly amazing to think about, that in less than 10 years during the decade of the 60's, the US went all the way from forming NASA to landing a man on the moon... And just this year the US stopped manned space exploration.
It should be noted, that the recent bank bailout would have funded NASA's entire budget for the last 50 years.