I've been enjoying the OP to To Aru Kagaku no Railgun. The happy, energetic music suits the show so well.
But I didn't realize that seiyuu Nanjou Yoshino 南條愛乃 is now the voice of fripSide until I saw the PV:
I was one of a vanishingly small number of people who liked her character Koko in DC II: Da Capo II. I think lots of people liked her as Maria in Canaan. She plays a character called Maya in Railgun
I did know that she herself was quite attractive (see photos below), with rather unique features. But I had no idea she could sing like this. Not that what she does in this song is that complicated, and not that her voice may not have various electronic assists here, but it really works.
fripSide was formed in 2002 by female vocalist/lyricist nao (now aged 24) and male music producer sat (Yaginuma Satoshi 八木沼悟志, now aged 35). They were a fixture in the doujin music world until 2006, when they joined the Visual Art's agency and started doing game music. In 2008, they did the Koihime Musou OP "flower of bravery."
In March of 2009, nao announced that she was leaving the group. In July, Nanjou (now aged 25) was announced as her successor. Nanjou doesn't have that certain something that nao did, but still sounds good. I look forward to nao's rumored solo career.
Japanese Wikipedia compares the group to I've, eufonius, and Elements Garden. It says their music is based in techno and J-pop, but that sat's keyboard work introduces elements of Euro-beat and trance.
Here is the fripSide PV of "flower of bravery," with nao and sat:
You can search YouTube for lots more of their music.
Here are some photos. Mouseover for captions, click to enlarge:
fripSide Wikipedia page (English)
fripSide home page
Nanjou Yukino jp.Wikipedia
Nanjou Yukino home page
Nanjou Yukino blog
Nanjou Yukino ANN (English)