Since my collection is MOSTLY Christmas pins I have many favs...
Series pins: Would have to be the Hometown Holiday pins 1998 and 1999
All of the DL Cast Season's Greetings pins are dear to my heart.
I have to agree with NHL fan for the vote for the Candlelight Ceremony pin. It reminds me that not only did I get stuck trying to pass through the US while they were filing onto the stage once....but TWICE!! Looks like I would learn.
My 2000 Dopey carrying a sack of presents brings special memories because Bkeating ( sp?) traded the pin with me. Then I got to meet the Bkeatings at WDW. Way fun!
Disneyana Auctions: The Fireplace pin. I have a deep affection for BAP's
Disney Store: Goofy hanging from HO HO...makes me chuckle every time.
All the pins from Tokyo DL are really nice. Esp. the M and P pins ( more BAP's)
Perdita ( my poly buddy) I like the M/M skating pin too. It's ROUND!!!
I think I am finished. There are many more that I like but you said just one

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Holy Grail: 1998 Hometown Holiday Pluto ( in case there is ANYONE out there that doesn't already know this!)
Susan