Kingdom Hearts and Kingdom Hearts 2. These games both have such an extensive list of characters that the voice acting really gets passed around and there isn't really one stand out role. Some highlights include Haley Joel Osment from the Sixth Sense as the lead character Sora, Hayden Panettiere in a pre-Heroes role as the lead damsel in distress Kairi and a slew of returning Disney voice actors to fill out the Disney cast.
Where it really gets fun though is when you start looking over the voice actor choices for the Final Fantasy and original characters. Some fun ones that make me scratch my head? Lance Bass voiced Sephiroth in the first installment. Yes, Lance Bass, the member of N'SYNC plays Sephiroth. Christopher Lee from Lord of the Rings and a slew of other fantastic films voices Ansem the Wise in Kingdom Hearts 2. Overall the entire cast is solid, which is good, as most of the games are voice driven, aside from some text based menu's here and there.