i have bought a car by wire transfering the money into the guys account while he was stood next to me. He then called his bank to confirm the money was there and then he handed over the keys etc. No worries on either part.
If you are accepting a bankers draft, ask for issuing banks tel number, get all numbers/details etc off the actual draft and ring the issuning branch and get them to confirm the details on the draft.
Do this before they turn up with it and check all the details on again when you actually see it!
just my 2p
I would only be happy with a bacs transfer, if they are genuine they will pay this way if you request it!