I have a hard time picking what seiyuu I like in order. But to me, my favorite would have to be Kaori Nazuka. To me, she seems like a very underrated seiyuu. I like most of her work from Miyu in
Daa! Daa! Daa! to Eureka from
Eureka Seven all the way up to Lynnette from
Strike Witches and Ayatsuji from
Amagami. Not to mention Totori from
Atelier Totori/Meruru. She has that sort of charm in her voice that I find very attractive. And being that she's done this since age 14 up until last year, I have a lot of respect for her. I could even say the same for Miyuki Sawashiro. They're both very talented and fun to listen to.
Other seiyuu I like (in no particular order):
Yui Horie
Rie Tanaka
Yukari Tamura
Marina Inoue
Eri Kitamura
Mamiko Noto
Mai Kadowaki
Misato Fukuen