I currently have a D3000 and I'm looking to upgrade. I am torn between buying a new D5100 with a 18-55 kit lens for $750 or buying a recertified D90 (body only) for $675. I already have a few lenses (DX format: 18-55, 55-200, 50 1.4, 18-105; I also have a 50 1.8 that isn't DX). Any help is appreciated