Ironically enough, the one that started my collection was the one that started ALL Disney movies!
I started my collection with Snow White and the Seven Dwarfs: Platinum Edition in August, 2005.
The reason I even started my Disney collection was because I had been reintroduced to Disney when I went to Disney World in July, 2005, and I loved it (again), for the first time since I was little (I went in April, 2004, but that didn't have much effect on me).
Then a month later, my brother needed to go to GameStop to get a gift card for his friend, and there was the DVD. Staring at me with its shiny "Platinum Edition" banner, and its $16.99 price tag. All inserts. Flawless discs. I had to get it. So....
I did!

Then came (in order):
Bambi - Sept. 2005
Beauty and the Beast - Oct. 2005
Cinderella - Oct. 2005
Aladdin - Oct. 2005
The Lion King - Oct. 2005
Sleeping Beauty - Nov. 2005
The Lion King 2: Special Edition - Nov. 2005
Mickey's Once Upon A Christmas - Dec. 2005
Mickey's Twice Upon A Christmas - Jan. 2006 (

Atlantis II - Jan. 2006
Kronk's New Groove - Apr. 2006
Lady and the Tramp(Platinum) - Jun. 2006
Beauty and the Beast: The Enchanted Christmas (SE) - Jul. 2006 (found it new for $14.99!)
Beauty and the Beast: Belle's Magical World (SE) - Aug. 2006
The Little Mermaid (Platinum) - Oct. 2006
The Fox and the Hound (Gold) - Oct. 2006
Cars (Widescreen) - Nov. 2006
Chicken Little - Nov. 2006
Lady and the Tramp (Limited Issue) - Nov. 2006
101 Dalmatians (Animated) [Limited Issue] - Dec. 2006
I got NEMO and THE INCREDIBLES before the Disney trip in 2005, but they weren't really the START of my collection!
What about you guys? (You don't have to post your entire collection and stuff like I did)