Normally, I'd say you want it opening as the top diagram. There is no rules, as he says. However your situation is weird due to the placement of the doorknob and locks on the front door.
It seems awkward either way. If you use example #1, the door knobs/locks DO NOT line up with each other. You'd open the storm door, and then reach across to the door's hardware to open it on the other side. Unusual. However, if you go with option #2, the storm door opens outwards at you when you pull it open. Imagine you have stuff in your arms and you're trying to open the door AND back up to get out of it's way, squeezing around it against the wall to get to the actual front door to open it.
So basically, both ways are awkward and less then ideal. However, of the two, I think option #1 will be the least headache, and easier to let people and goods in and out of the house.