Melody from Pokemon 2000 because of her mad ocarina skills
Not my first, but I did get paired off with her at one point.
Mine first was Serena Tsukino. Until my aunt embarrassed the hell out of me over it, and I realized that she was a ditzy dumbass valleygirl, not real, and way too old for me (I was 4). I reacted so badly that I swore off "these stupid cartoons" till I was 9, and Monster Rancher came out.
You beat me to it
Great taste though