Seiyuu are
very important to me, I watched numerous series just because my favorites voiced characters in them.
And some of my favorites would be:
Satsuki Yukino - I'm in love with her voice. I liked her since Saki Kasukabe in Genshiken, but only after watching Planetes and R.O.D. the TV one after another she became my favorite. I like her so much in fact, that I'm planning to watch Inuyasha one day, for the sole purpose of hearing her voice. And I watched some series just because she voiced characters in them. I think one of the reasons i like her is that she is great as a meganekko(R.O.D., Pani Poni Dash), and I just love girls with glasses.
Yui Makino - she's much less versatile then Satsuki Yukino but even if I only saw Welcome to the NHK, I'd still like her. Great, unique voice, and I love her singing. Go listen to this, if you haven't already:
http://www.youtube.com/watch?v=sM3dw5Yt1kQ She really needs to get more roles.
Ryoko Shiraishi - her voice acting caught my attention in Zettai Karen Children, and I liked her ever since. For example, my favorite character from Mahou Shoujo Lyrical Nanoha was Miyuki, only because she was voiced by Ryoko Shiraishi and wore glasses. And yeah, she is another of my favorites that plays girls with glasses.
Maaya Sakamoto - great seiyuu and great singer. I especially loved her in Top o Nerae 2, and of course Kara no Kyoukai. Another unique, unmistakable voice.
But really, I could go on all day, there's a lot of great voice actors and actresses.
Megumi Hayashibara
http://en.wikipedia.org/wiki/Megumi_Hayashibara
She's a legend, if you don't know who Megumi Hayashibara is you should be ashamed of yourself
