Finally, a discussion of Pluto based on reasoned argument and not emotion!  Thank you all for your perspectives.    Science, in this case, planetary science, is self-correcting.  Something is found, it is fitted into current knowledge and when further research is conducted and the situation changes, so does the perception of  the object found.  Pluto was always an enigma.  It was a square peg trying to fit into a round hole.  To understand it all, one should look at the historic perspective, which has not yet been mentioned on this thread.   Neptune was discovered due to a perceived gravitational effect on Uranus.  Planet X, so named by Percival Lowell, was predicted due to a gravitational effect on Neptune.  Lowell looked for it for many years and did not find it (actually he did, but missed it - the earliest photos of Pluto date back to 1909).  When Planet X, soon named Pluto, was discovered, it turned out to be another mystery rather than a s olution.  Pluto's size in 1931 was determined to be approximately that of Earth, still not large enough to cause the perceived gravitational effect needed on Neptune.  Then it's orbit was determined. While all the known planets at the time were approximately 6 degs off the plane of the solar system, Pluto was a whopping 30 degs off.  Square peg indeed.  By 1948, Pluto's mass had been reduced to that of Mars and by 1976 it was determined to be 1% of Earth's mass.  In 1978, when methane was discovered in Pluto's atmosphere, it was decided methane caused an object to appear larger than it was and so Pluto's mass was reduced yet again to 0.2% of Earth's.  With Voyager 2's flyby of Neptune, it's size was reduced and the need for any object having a gravitational effect on it's orbit disappeared altogether.     When the Kuiper belt was first proposed and/or named, it was theorized the belt was to be found between 30-50 AUs from the sun and between 30 degs, either side, of the solar plane, not specifically mentioned, Pluto was smack dab in it, at 40 AU distance and 30 degs from the solar plane.  Further research determined Pluto's composition to be that of rock and frozen volatiles, in other words, ice.  Similar composition to a comet.    Perhaps the icing on the cake (or the nail in the coffin - depending on your perception), in 1992 the first official KBO was discovered.  Since then over 1,000 KBOs have been found.  Since 2000, 14 KBOs half the size or larger of Pluto have been discovered.  Most have been named, some have not.  Further research determined Pluto as well as a number of other KBOs are in resonance with Neptune.   If it looks like a duck, acts like a duck and quacks like a duck - it's a duck.  It may be the biggest duck/goose/bird out there, but it's part of that family.  Pluto has challenged our perception of the solar system, what it is and how it formed.  Human understanding of the system has evolved and continues to evolve thanks to Pluto.  Pluto is unique, it has a twin (Charon) and by it's size, small as it is, has managed to capture a few KBOs to make a small country (or system).  It's fascinating in its own right and continues to challenge humanity.     Yep science is self-correcting and continually evolving, which is one of the great things about science!