I love Amigurumi! I think it's the looks on their little faces and the maternal instinct coming in. In fact, it was discovering amigurumi that really got me into knitting regularly in the first place. In particular, discovering one website: Mochimochi Land. I love it. I have 3 of her patterns and preordered her book when it was first announced.
In fact, I only own 2 knitting books, and they are both on amigurumi