Whats the best anti-theft device for a bicycle

Tie a mountain lion up next to the bike.

a bike lock? and just wrap it through tires and frame so if anything all they can steal is one tire if anything..thats if your in the ghetto

a lock

tie it up to a grizzly bear =D lol. just kidding.

remove the rear wheel and take it with you. Thiefs will want a bike they can just ride off on, this to make them seem like they are the owners of the bike.

Locks, and know how to use them. Use a good U lock to lock the back tire to something solid (going thru the rear triangle). It is good to use a U lock and a cable lock at the same time. You can also fill in the allen screws on components with something to prevent them from being removed quickly. You can buy lockable quick releases, l think they are called Bull Dog.

http://missinglink.org/Pages/bike_locking.html

The best lock is no lock. Do not ever leave your bike unattended outside and it will never be stolen. If you must lock your bike up a good u-lock or hardened chain around your front wheel and frame will keep all but the most skilled and persistent thieves away.

Keep it indoors or with you at all times.

The classic POS bike.

Glock 19. Compact frame but plenty of knock-down power, especially if used with a high-p hollow point.

Edit: Note to MR. You have obviously never lived in in-town Atlanta, or a similar urban area. Have had MANY bike stolen while securely locked up and out of sight in home, garage, and windowless dead-bolted storage building. Life is rough in the urban jungle, and they will steal anything. Central alarm system just makes them work faster and break more things.

do not ever take your eyes off your bike and carry your bicycle whenever you will need to go indoor.