>>1947715a chain and padlock is the only correct answer
dont buy a bikelock they all suck
also if you habe quick release wheels or seat buy a long thin peice of chain to put through them
i see bikes with no wheels or seat all over the place
also be careful what rack you lock to
if its got locks on it but no bikes thats a bad rack
i find racks near busy roads are the worst for this
you can lock to other stuff too but id be very cautious about where
never leave your bike outside overnight