There are some cool-looking hammers out there these days. These fist-size lumps of highly polished steel with wicked-looking claws and long, shaped handles are great—if you frame walls for a living.
But for most work around the house, you're better off with a 16-oz. claw hammer—the same kind most carpenters use when they're not framing. A quality one will cost $25 to $30. Although straight-claw hammers look more powerful and are better at prying, a curved-claw model is more compact and better at pulling nails. You can drop down to a 13-oz. hammer (the weight is stamped on the head) for trim work, and you might want a 20- or 22-oz. hammer for framing. But don't be tempted by those 24-, 28- or 32-oz. monsters.
There are four handle types to choose from: fiberglass, graphite, hickory and steel. Hickory handles are comfortable, but heads can work loose and may need periodic reshimming with steel wedges. Wood handles can also break with vigorous nail pulling or repeated overstriking. The head and handle on all-steel hammers are forged as one piece; that's great for strength, but your hand and wrist bear the full force of each hammer blow. Updated designs use fiberglass or graphite handles, which are recommended for their durability and shock-absorbing qualities.
Unless you're building an addition, avoid a checkerboard face (also called a mill face), which is designed to reduce glancing blows and flying nails when framing. It leaves marks on wood or walls even when nails are driven properly. A smooth-head type is your best bet.
For the grip, look for a comfortable rubber coating that will keep the hammer from slipping from your hand. While we're on the topic of safety, never strike one hammer face with another when you're prying something up—the tempered rims can chip, creating flying shrapnel. And take the time to put on safety glasses—it only takes one misstruck nail to take out an eye permanently.