I sort of don't know. I used to watch Pokemon, Cardcaptors (now I watch Cardcaptor Sakura ^^), and Sailor Moon when I was a little kid, but I don't think those count as "the line-crosser". I think the line crosser for me was Tokyo Mew Mew (it's scary, but true), and that's when I took the plunge into the wonderful world of manga and anime.

Eh, on second thought, Naruto was what got me deep into anime.