It depends entirely on time of year, what else is going on in the schedule, whether I'm going to be working OT that day, etc.
This time of year, I'm working a couple of hours of OT a day but I like to be home around when the kids get home. I go to bed around 10PM, wake up at 4AM, get my food ready and in the bag, get on the road around 4:30, in to work around 5:15 (11 mile trip in the winter = 45 minutes). Once there I cool down for a bit while reading my email, then shower, get changed, eat my breakfast and get to work. I try to leave around 3PM.

I typically spend about 2 or 3 minutes in the shower, unless I'm shaving, in which case it's 5, but I turn the water off while I'm shaving. I don't know what they hell I'd do in there to take 20 minutes. Dressing is about 2 more minutes. Typically I'm back at my desk and dressed about 8 minutes after I left to take the shower.

I don't really have to be at work at any special time. I usually put in another hour or so, 10 minutes at a time, during the evening, logged in from home and checking on systems.