Is this the most influenced from anime of the millennium so far?
You mean "influential"?
Yeah. I keep forgetting how to spell that.
If you mean 'influential', that would be Love Hina. Sadly. It basically set of hundreds of formulaic anime clones that followed the Naru/Keitaro formula. Even series like Haruhi, Toradora, Boku wa Tomodachi ga Sukunai and Working!! can trace part of their formula and popularity to Love Hina.
Azumanga Daioh is high up there in imitators and popularity as well. But nowhere near Love Hina.