remember to run uptime in the terminal to see if its one of those constantly rebooting n900's.

to see if its fake, see if there is a magnet on the kickstand and on the cover directly below the other magnet on the cover. I doubt fakes would keep this detail.

make sure the usb port isn't wiggling like crazy, if you push down with your nail gently, there should no no give.

Do the transaction in a very crowed place with an ATM, there's a free ATM in the ING cafe on 58th and 3rd. Or meet outside the police station on 51st and 3rd..