The standard shape, and for good reason! Every kitchen should have at least one good standard chef knife. Anyone can cook an entire great meal with just this one knife, so don't be tempted by some fancy new trendy knife style before you have one of these workhorses in your stable. For home use (and for most pros), 8" (or 210mm which is about 8.3") is the way to go: not too big, not too small, fits most knife blocks and other storage systems, and can easily be handled by just about anyone with any size hand. After you have a good 8" chef knife, only then should you really consider something longer or shorter.