The Ekto 2 is an extremely durable, well-designed lightweight case that provides a layer of protection usually reserved for heavier cases.
With a lightweight polycarbonate shell and man-made leather backing, the Krusell Luna Mobile Undercover case keeps the back and corners of your iPhone 4 safe, but little else.
Most iPhone case/wallet hybrids haven't been that impressive, but with the CandyShell Card, you really can consider leaving your wallet at home if you only need a few necessary items.
Incase's Metallic Snap Case is a metal hard shell case that’s both thin and lightweight. It provides protection and coverage comparable to what’s usually found in more substantial, heavier cases.