To me, MK4's voices (especially Raiden and Jarek's voice) were and always will be the best, there are certain elements about MK that should be over the top and one of them is the voices, the in game grunts and moans should be crazy and very animated, like in MK2-4 especially and to a lesser extent MKDA-MKA, not the boring crap we get in MK Vs DC - MKX, I'd say for the more modern games I did like Reiko, Quan Chi, Shang Tsung/Daegon, Bo Rai Cho, Jarek, Mileena, Jade, Scorpion and Rain's voices in Armageddon, they mostly fit the characters well too.