My very first idols? I dunno, I know UTAU since so early (I could only record after I got a computer with enough disk space)... I can guess it was Zanda, not sure. I think I also liked Mako and Momo a lot xD;
When I started to record Aline, I liked Tony Yonne, Camila Melodia, Fuuga Koto and Donka Fjord.
A bit later on, I started liking Nanto Natsuki a lot, she's still one of my favorites. I also liked Otouto Shinjitsu, but after a lot of voicers started making their little siblings record UTAUloids, as well as Yuki Kaai and the voiceroids appeared, he lost a bit of his appeal ^^;
Until a while ago, it was Hachi-Yue-Mathieu-Natsuki, in that order. But now, it's more like Natsuki-Mathieu-Yohji-Tama and then, Hachi and Yue in the same order. I think I want to include Nath Natsume, but I'll need to wait a bit more until her design is fully colored and stuff 8D;
(In case you're wondering, go check out Seishoubo Tama. She has a deep and motherly voice, it's awesome.)