I agree with Zazaku. I usually go Ring for AP and boots/pots or cloth/pots for anybody else. If I'm top lane vs. another ad, I almost always go cloth/pots.
Also, if you notice you went cloth/pots and they went doran's blade, don't try to kill them in one swoop unless you have the clear advantage. Exchange blows, use a pot, and outsustain them. If you try to fight them when you're both at full til one of you dies, you're at a huge disadvantage. On the other hand, if you make use of pots and simply out sustain them, steadily pushing them away from creeps and denying them, you're making more effective use of your starting items.