Chiyo-chan in the cat outfit and the penguin outfit in Azumanga Daioh.
CardCaptor Sakura is full of cute moments, but the first hint I had that it would be a super-cute show was when she laced up the skates for the first time.
All kinds of moments in Aishiteru ze Baby, mostly when Yuzuyu is drawing/creating stuff. Marika has her cute "crushing on Kippei" moments too.
Haibane Renmei: One of the later episodes when they make wing covers for cold weather. The episode with the bell communication is good too.
Fruits Basket: some scenes in episode 17 where they show Kisa with tiger features (not as a tiger, but when she has the ears/tail)
Shuffle!: Episode 22 with Ruri, I mean, Primula in the "feline maid" outfit, complete with prehensile tail
Full Moon wo Sagashite: Whenever Meroko transforms into rabbit form and starts beating up on Takuto.
That's enough for now, though I'm watching Snow Fairy Sugar right now and seeing even more cuteness
![Very Happy :D](./images/smilies/icon_biggrin.gif)