I had a copy of my bankbook with me but they did not ask. Copy of my rental contract was included in the school paperwork. Can't hurt to bring more docs than needed. :)
Went to HCM last week. Arrived Monday morning around 8:15 at the consulate and I thought I had the wrong address because no one was there. At 8:30 two more people showed up. Gave them a filled in visa application form and the documentation that the school preparedfor me. Cost USD80. Pick up next day, also very fast. Make it a city trip. Saigon is a nice city.;-)