Now I know it's not the most beautiful, cute or enchanting collectible, but I love it so much because in the ACNL picture contest, all I did was decorate one of my rooms to recreate the scene of "I don't need it" from Spongebob. I used the glass flower vase as a mockup for the Tetris Grid. I still have the image stored in my 3ds SD card. I also believe someone else did the same scenario with the Crescent Moon Glow Wand with the Mr. Turner "If I had one" scene, the fact that both of us won a non-tradable collectible by using a Nickelodeon cartoon is bizarre and funny.
It was refreshing being on the winning team for once (sorry Buzzy Bees) and its one that means something to me. I love the mix of purple and blue, two of my favourite colours. I'm not really into the other non-tradables. Pretty as they are, I don't have them so I don't have any feelings attached to them.
Green pinwheel & rainbow feather are my two favourite non-tradeable collectibles. Forever sad that I'll almost certainly never own a rainbow feather because I don't have the artistic skills to win any contests but at least I miraculously won a green pinwheel!
My top 3 are Echanted bloom, heart of the forest, and the lost book.
I also really like the bronze trophy, because I got it from a writing event. I'm not a great writer, and sometimes my sense of humor is a bit off, haha, so it was nice to have a story actually do well.