Hit 85 on the shadow priest today - so that's #6! Interestingly enough, it was also my fastest leveling time to date. My total played time to 85 from 80 was 21 hrs, 28 minutes.
My previous best was the enhance shaman at 23 hrs, 10 minutes. Of course, there were two different elements to this. I don't have any professions on this toon, so no extra time for that. I also didn't do a single dungeon on this toon.
So, now I'm on to the death knight.