damn, sorry to hear that BND. My car was parked right next to yours too. I think I'll have to examine my car later to see if anything was missing.
I think I'll take my keys out of the ignition now after hearing that. I left the keys in there the whole day too. And even left my phone on the dash unattended. I would have gone POed if someone took my phone.
Have you tried searching your car, maybe it's underneath the seats for some reason.