Hey! I have stuff to say!
They should've let all those other things out in space be planets, because they have cooler names than the pre-existing planets. I mean, Uranus? Mars? Venus? Seriously, they make those hunks of rock floating out in nowhere sounds as boring as... well, hunks of rock floating out in nowhere!(Orbiting, whatever). Jupiter sounds cool, though. And Saturn. Earth sounds almost boring, because of it's monosyllabity, but it's pleasantly weird the more you think about it. Why not have planets called Xena and Cerenosi and Geoba or whatever? I can't wait to take Sci-fi and Fantasy class next year...
As for Pluto, that planet was named after a smart guy, no? Or is that Plato... Well anyway, why isn't Pluto a planet? All I read was "Pluto's not a planet anymore".
And I never used a nmemonic device to remember the planet's order. Or at least saying them all in sequence was easy enough to remember.