Back in April, I reserved my WiFi-only iPad, but I got up very early that morning anyway and headed on over to the Apple store. There were already a few people in each line (one line for those who were picking up reserved iPads and one line for those who had no reservations). That was at something like a little after 6:00 AM. By the time the store was ready to open there were quite a few people in both lines. It was fun to be there early in order to see the unveiling of the new iPad when the employees removed the drapes from the store windows.
I probably will do the same thing again for the iPhone -- go and get in line very early. My Apple store is in a mall and on Apple launch days they have arrangements with Security so that there is one entrance unlocked very early in preparation for people who are arriving before the crack of dawn.....
Sounds exactly like my experiences for the 3G and 3Gs.