Look, you can enjoy someone as the best character without being into them sexually. The fact she's the smartest and most mature of the three despite her age and is willing to put up with all their bullshit is what makes her the best.
@Saike
Also, the best idols group is Gorillaz because they're a satire of it by making them the least attractive, most morally questionable group of assholes possible. Because they believe you should reject false idols and have the music come first. Apart from Noodle, who is underage for most of the series, they're all not very attractive and they don't play into any fantasies one might have. That's what makes them the best virtual group because its about the music, man!