Actually, I prefer the "killing field" strategy. As we know, barbarians like to appear in places where cities aren't built yet... and they appear often. So I like to find a nice mountain square, and park a pikeman, a mounted unit, and a diplo in a location that is just closer to somebody elses city. Barbs appear... bribe a few for non units, and let the remainder attack my fortified pikeman, watch them die, then hunt down the king for money.
When done right, there is nothing better