1a: FFXII. Incredible voice acting. No words can do it justice.
1b: Have to go with FFX. But that' understandable, seeing as it's the first voiced FF.
2a: Balthier & Fran. God, I could listen to those two day and night. Balthier's way of speech is so smooth and great to listen to, while Fran has one of the most incredible voices I have ever heard. And that accent...
2b: I didn't like Rubicante's voice from FFIV DS. Although the voice-acting was OK in that game, he sounded terrible.