I also discussed with satoshi, and he said that his employers at the NSA wanted him to create the first P2P currency with a back door in it. That back door happens to be in this specific elliptic curve. Government supercomputers searched for a random elliptic curve that contained a back door.
Just joking, but that's my conspiracy theory. Actually if there is no particular reason for this elliptic curve to be chosen, that is actually suspicious...

We can't do anything but speculate, though. Earlier, it's said Satoshi picked it "just because."