I’m not a fan of Aya Hirano. While I think she’s talented, I’m just not swept away by her voice acting the way I am by, say, Shizu-sama or Maaya Sakamoto. That said, I have enjoyed her work as Haruhi Suzumiya (megalomania ♥) and Shizu Shidou (Ijimekko~~) but, to date, my Top Favourite Aya Hirano role has to be Konata where she really made the role her own, conveying the chara’s distinctive blend of otaku passion, family/friendship love power and :3
Not that I agree, or even know anything about Aya, just wanted to preserve it.
My own understanding of seyuu is about nil. I fondly remember Mitsuishi Kotono. Rie Tanaka always impressed me with her professionalism and enormous range. She's still in business, recently playing Lt.Col. Wilcke in Strike Witches. Also, I remember a couple of "one role" seyuu, whom I probably would not recognize again: Marina Inoue as Tsukiumi in Sekirei, and Natsumi Yanase as Chihiro in ef (I understand that Mrs. Inoue is quite well known, just not by me). Currently I keep meaning to look up who plays Sumire in Toradora — it's another distinctive performance. Aya though? I remember Konata but not Mrs. Hirano.