I'm a solid two-putt from just about anywhere on the green (this isn't to say I don't three jack, I just don't do it very often). If I'm out side 10 feet, I'll always play the general break - which is the way I figure most of the putt will move. So if the green is higher on the left and lower on the right, I'll usually give myself 3" to the left for the first putt.

That being said, inside 10 feet, like Greg said, the last 3-5 feet of break is the most important, as it will wreak havoc on a ball with the proper weight. (Little tip - a fast moving ball tends to ignore break... and will similarily ignore the cup, too )

Then I try to figure out (strictly art here, not much science) how much the ball will move between it's current placement and the hole. I aim to a spot beside the hole on the high side of the break, and give 'er a tap.

Remember: If you three putt, it's because your first putt sucked!