No disrespect, but I disagree. Unless I'm misinterpreting. It depends largely on the style of map you're making. You may want to take a look at Final Fantasy Epic RPG, it's not too annoying there, and quests tend to be important enough to demand a change to cinematic mode.
Chat on the left side of the screen works fine for conversations that should be heard by the entire party.
Floating text can be tricky, if you don't time it right so they have enough time to read, yet not too much... And if you accidentally make it permanent.
Dialogue boxes are a good choice, though... But I would recommend staying away from making the character say... simply... "Yes" or "No" too often.