I was one of those on line at the Grand Central store. I got there a little after 6AM and managed to get an AT&T 32GB silver and AT&T 16GB space grey. They had Verizon 64GBs only by the time they got to me. T-Mobiles were also out of stock when they got to me but that's irrelevant really. The Chinese people at the front of the line ate up a lot of the 16GBs.
I tried waiting at Manhasset on Monday morning. I got there at opening with a modest line of people in front of me. We waited for 3.5 hours before an employee finally came out to tell us that they had no stock and were not expecting any for the day. After that experience, I will never go to a small store like Manhasset for a release.
Grand Central seems to be the best bet. Get there early enough and you'll pretty much walk away with a phone. The employee who I checked out with said they get at least 100+ phone shipments everyday. By the looks of people waiting on line with the cards, it seemed like they had 250+ for today. Just be careful with all of the sneaky people trying to cut the line and bum rush the bottom of the stairs. A lot of people were very passive aggressive and let people cut without saying anything.