Not counting random episodes of Pokemon and Yu-Gi-Oh I saw on TV, it was Tokyo Mew Mew. I wanted to watch something truly 'anime' and not just another cartoon I could find on TV. At the time, I thought that meant cat girls fighting evil. Tokyo Mew Mew was one of the recently released shows when I went looking for torrents online.

I wouldn't say Tokyo Mew Mew made me an anime fan, that came later when Haruhi Suzumiya came out and that's when I truly loved an anime. I still go back and watch it from time time (well parts of it anyway, endless eight kinda ruined it). Toyko Mew Mew is very mid and not something I've ever rewatched. I think it was surprising solid for what was essentially a knock off sailor moon, but it's not a show I'd suggest anyone else to ever start out with.