The last few posts re barbs intriuged me, so I fired up a new Diety game with Pacal (raging barbs; post-patch) and proceeded to do nothing to try to stop the barbs. Never fired from the city and never built any military units (sent my initial warrior off exploring, to keep him out of the way, and collect gold from embassies, CSs and ruins), but also never improved any tiles (never built a worker), so there was nothing to pillage. Several barbs (initially 2 brutes, a spearman and an archer) eventually made their way to my capital and danced around for about 30 turns, but never took a shot at my capital. Very disappointing.
What happened was fun though. Since you have to build stuff as you hit "next turn," I built a monument and then a pyramid and a granary, got a pantheon (threw it away on 15% border expansion), started building the only wonder I'd researched (Temple of Artemis) and I GOT IT. Isabella promptly DOWed me, and I paid Atilla to declare war on her (he turned out to be worthless, by the way).
She initially showed up at my capital with 6 warriors and a chariot archer and later added two catapults, another chariot archer and a horseman. I did have the city shoot at her units, and the barbs ate 2 of her weakened warriors before she killed/chased off the initial bunch of barbs. I kept taking pot-shots at her units, killing both cats and taking 7 turns to build walls (her tactics were not inspiring). Two more barb spearmen arrived and I worked with them to keep knocking down her invasion force (the barbs were my ALLIES). When she took out those barbs, and was starting to beat down my walls, I broke down and bought an atlatlist and started building another. I took out a few more units and, when the second atlatlist popped and killed her last warrior, she limped away with only her horseman and a wounded chariot archer.
Definitely the most fun I've had on Diety in weeks.