cash all the way.
I'll always remember seeing this guy buying a car from my parents when I was a wee lil kid. Leather briefcase, a couple tools inside it to remove something from the car, and a fat stack of cash. Impressive, but the most tangible form of money if one doesn't take into account deflation
Bankers draft and bank transfers are the only other good options.
Anything like maestro transfers, western union(ah!), personal checks etc should be avoided.
From the possibility of there being a financial issue somewhere along the line, to extra incurred fees(looking up relevant information wouldn't hurt if that's the route you intend on taking) cash is the most hassle free option.