She started as Ran@Texhnolyze and Akiha@Tsukihime, who were not the most significant roles, but after rewatching the shows I appreciated that she didn't screw up two very complicated characters. But was stereotyped into serious, mature for her age young girl roles... nonetheless was very effective at them.
The other impressive role is Kaori@Index, when in the beginning of the first season she snapped and beat the shit out of the MC.
I was impressed when she played Naoto@DOGS, because in her episode she had to act briefly the various psychological stages and social circumstances the girl had been through, and did an amazing job in this very demanding role.
After that she gets more variety in roles, but hasn't impressed me as the ones I mentioned already.