deac,
In most bar games it's either #3 or #2 behind the head string.
The official rule: "4.19 PLAYING THE 8-BALL
When the 8-ball is the legal object ball, a scratch or foul is not loss of game if the 8-ball is not pocketed or jumped from the table. Incoming player has cue ball in hand. Note: A combination shot can never be used to legally pocket the 8-ball, except when the 8-ball is the first ball contacted in the shot sequence."
http://www.bca-pool.com/play/tournam.../rls_8bl.shtml
So the official rule is #2 w/ cue ball anywhere on the table.