^ Same as above. It's always fun to hear a familiar voice and finding out if it really is the one you're thinking of (sometimes it isn't, sometimes it just sounds similar). And then of course it's also fun to look up what other characters they've voiced.
Let's see... well, Wakamoto is really easy to spot. And he voices Houzuki in Sharin no Kuni. Epic commanding voice indeed.
Love Nakahara Mai, the seiyuu for Ryuuguu Rena in Higurashi and also Furukawa Nagisa in Clannad (though I haven't read Clannad yet). She's just great. Can be cute, can be serious, can be creepy. You don't actually get to hear her voice in the English translated PC VN of Higurashi though since there's no voice acting patch.
Tamura Yukari who voices Rika in Higurashi, plus another character in another VN whom I shall not name. Very adorable voice, but of course... has other tones to it as well. You might know what I mean.
Taguchi Hiroko, as Sumika in Muv-Luv, Natsumi in Sharin, etc. Memorable and good all-around seiyuu.
The voice of Kotomine Kirei in Fate/stay night - Nakata Jouji. "-------------------------------------Emiya Shirou-".
Sawashiro Miyuki. Overall really skilled seiyuu in my opinion. She's got quite many roles in anime, and I've heard her in at least two VNs - Umineko and Danganronpa.
Oh and thumbs up for every voice actor in Umineko. Phenomenal work there. Not gonna list every single one, but they were all great.