[drpullockaran]

The first forum article below is real good though very short.

DDR2-667 and DDR3-1333 bandwidths with 333MHz FSB

AnandTech: DDR3 vs. DDR2

Legit Reviews - Intel P35 Chipset: DDR2 Versus DDR3 Memory - DDR3 Finally Enters The Market

DDR2 vs DDR3: The Battle of Latency vs. Bandwidth - Asus P5K3 Deluxe WiFi & Corsair TWIN3X2048-1333C9DHX Review - Page 1 - Introduction

DDR-2 vs. DDR-3 Memory – An exhaustive look at the Intel P35 platform :: TweakTown

DDR2 and DDR3 Memory Round Up - TrustedReviews


Finally you have to consider cost versus performance.