/played to 70 (Death Knight)
37 hours, 45 minutes, with normal play (no crazy powerleveling, items/cash sent from an alt, etc.). Even with 55-58 being pretty quick gimmes, that’s less than 3 hours a level. Leveling time basically ramped up from 55 until 68, then ramped down for 69-70. (And then 70-71 was dreadful.)
The leveling was over about 37 days, so I think that average shows an admirable amount of restraint on my part. 