There were some reports on NeoGaf and other places that suggested that eager Smash Bros. customers in formed a line "at least three blocks long" at the Nintendo World store last night. Three blocks sounds like a lot, but it's actually not as big a line as you suspect.

People, on average are just a smidge over a foot thick. There's also a lot of studies that show how far apart people are willing to stand apart from one another. According to the famous Anthropologist Edward T. Hall who studied this topic rigorously, the average for most people, interacting with strangers is about 28 inches for the front and 16 inches behind. Americans tend to prefer a little more space on average, but New Yorkers specifically (as well as anyone that comes from a big city) are generally comfortable with a bit less. We could safely allocate around 40 inches per person. This gives each one the appropriate space in front of and behind them as well as account for the typical body size with the overlapping portions of each person's bubble cut out.

Next we need to figure out how long our blocks are. Now I've never been to New York, but photos from the area cross-referenced with Google Maps shows that Smashers are lining up on the long side of the block. Typically, long blocks in New York are 750 feet long. If we do the math there, we end up with 27,000 inches. With that, we just need to divide by 40 inches, and we end up with 675 people.

Just looking at one of the photographs (originally posted by antonz) seems to confirm that estimate too. Some folks are standing really close, others very far apart, but there aren't too many people in the shot. It's angled down 48th, showing almost half of the whole block. While I'll admit it's pretty rough, I only counted 56 people in the shot (I'm sure there were quite a few more obscure by trees, though).