Lithium-ion (Li-Ion) and nickel-metal-hydride (NiMH) batteries are helping cordless drills add power and run time, with less weight for Li-Ion. Greener design is also a plus, since Li-Ion and NiMH batteries don't contain toxic cadmium, which can leach into groundwater if spent nickel-cadmium (NiCd) batteries are thrown out with trash instead of recycled.

While most drills with these new-tech batteries still sell for $200 or more, you'll find more lower-priced models as more brands make the switch. But at as little as $100, capable NiCd drills still cost far less. You'll also see more impact drivers, which emphasize tightening and loosening power over speed, courtesy of a spinning internal hammer. But their striking action makes them loud enough to require hearing protection.

Black & Decker and Craftsman (Sears) are the major brands. Like Ryobi and Skil, they're aimed primarily at homeowners. Bosch, DeWalt, Hitachi, Makita, Milwaukee, Porter-Cable, and Ridgid offer pricier drills designed for pros and serious do-it-yourselfers. Most 9.6-volt models cost less than $100. At about 3 pounds, they weigh half as much as some 18-volt models, the typical voltage these days. You'll even find small, lightweight Li-Ion drills in that price range. But unless you're handling strictly light-duty tasks, you're likely to be disappointed with most sub-$100 drills. Price: about $40 to $100 for 9.6-volt drills, $50 to $130 for 12-volt drills, $60 to $200 for 14.4-volt models, $100 to $300 for 18-volt models, and $150 or more for most impact drivers.

You won't find all brands of drills and drivers at all stores. Craftsman is sold at Sears and Kmart, Ridgid and Ryobi are sold at Home Depot. Brands such as Bosch, DeWalt, Makita, Milwaukee, and Skil are found at Sears, Home Depot, and at Lowe's, which also sells Hitachi. Lowe's and Target sell Black & Decker as well. We also suggest considering an impact driver only to augment a cordless drill, not to replace one. Here's what else to keep in mind while shopping:

Some drills are bundled with other cordless tools and sold as kits that typically include circular and reciprocating saws, a flashlight, and a carrying case. Some kits are a relatively good deal, while others are a collection of mediocre tools.

Not everyone needs maximum power and run time. Nearly any drill will do for hanging pictures and other easy tasks. Most lighter-duty drills are lighter in weight. Decide how much speed and power you need. Then keep these tips in mind:

Don't go by voltage. Several 18-volt drills were bested by models with 14.4 and even 12 volts.

Look for work-saving features. The most capable drills and drivers have long run times, letting you do more work with fewer pauses to charge or change batteries. Recharge times of 30 minutes or less are another advantage. Some manufacturers offer a variety of tools without batteries and chargers so that you can power them with the ones you might already have.

Check battery prices. Some NiCd replacement cells cost as little as $25 compared with $90 or more for many Li-Ion and NiMH cells. While you can't share batteries between brands, some let you buy their 18-volt drills, saws, and other tools with or without batteries and chargers, letting you build a collection a la carte for less.

Skip the gimmicks. Some drills include items, like gel-filled handle pads, that didn't stand out in our tests. Our testers also found that the built-in laser levels on some models are difficult to use effectively.

Put your hands on it. Hold the drill or driver at shoulder height or higher to be sure it isn't too heavy for overhead work. Check that its grip is free of bumps and sharp edges, and that its trigger works smoothly. Especially with heavier models, be sure the tool feels balanced without tipping up or down in front.

Besides checking a drill's weight, check its balance by gripping it firmly and then lifting it to the wall as if you were about to drive a screw. The drill's chuck should point straight ahead and not tilt up or dip down.

Be skeptical about specs. Ads and displays often imply that more voltage is better, which isn't necessarily so. You'll also see impressive-sounding torque ratings (in inch-pounds) and maximum speeds (in revolutions per minute). Just don't expect the drill you buy to reach those speeds at home, since manufacturers typically conduct speed tests in the no-load mode--free-running without the drill bit. Our scores show which models drilled holes fastest, drove screws and bolts most powerfully, and ran longest per charge under demanding conditions.

See our latest Ratings of cordless drills and related information (available to subscribers).