When I change the oil in my wife's car, I let it drain for 2 hours, and by the time I go back out to put in the drain plug, it has totally stopped dripping by then. That's when I pour in a little bit of fresh oil, then wait a few more minutes and button things back up.
I'd like to wait that long with my 95 Formula, but I cannot leave my car parked up on the curb in front of my house for too long (they'll ticket us, as I'm in a townhouse) I park my car with two wheels up on the curb so I can fit under it, but with my wife's Honda, I don't need to do this. So I can leave the car parked in the driveway and let the oil drain as long as I wish.
When I lived with my parents and could park the cars on the curb without worrying about tickets, I used to let the oil in my 98 Formula drain for about 90min. I once measured how much more dirty oil came out between the 5min mark and the 90min mark, and it was 4 more ounces!! Most fast lube places don't even let the oil drain out for 5min either! (I timed the GM dealer when I got my oil change done there and it was only 3min that they let it drain)
Another major benefit of letting the oil drain that long is that when it comes time to change the oil filter, everything has cooled right off, so you don't burn yourself. When I had my LS1 that was a big thing since taking off the oil filter on them is a real mess, quite a bit of oil comes out of there.